Acknowledgment and/or receiver recovery mechanisms for scheduled responses within multiple user, multiple access, and/or MIMO wireless communications

ABSTRACT

Acknowledgment and/or receiver recovery mechanisms for scheduled responses within multiple user, multiple access, and/or MIMO wireless communications. Explicit scheduling information is provided from a first wireless communication device (e.g., an access point (AP), a transmitting wireless communication device) to a number of other wireless communication devices (e.g., wireless stations (STAs), receiving wireless communication devices) directing those other wireless communication devices a manner by which responses (e.g., acknowledgments (ACKs), block acknowledgments (BACKs), training feedback frames, etc.) are to be provided to the first wireless communication device there from. Such direction may include the order, timing, cluster assignment, etc. by which each respective wireless communication device is to provide its respective response to the first wireless communication device. In the event of the first wireless communication device failing to receive at least one response from at least one of the other wireless communication devices, various communication medium recovery mechanisms may be performed.

CROSS REFERENCE TO RELATED PATENTS/PATENT APPLICATIONS

The present U.S. Utility patent application claims priority pursuant to35 U.S.C. §120 as a continuation of U.S. Utility application Ser. No.13/218,537, entitled “Acknowledgment and/or receiver recovery mechanismsfor scheduled responses within multiple user, multiple access, and/orMIMO wireless communications,” filed Aug. 26, 2011, pending, andscheduled subsequently to be issued as U.S. Pat. No. 9,131,395 on Sep.8, 2015 (as indicated in an ISSUE NOTIFICATION mailed from the USPTO onAug. 19, 2015), which claims priority pursuant to 35 U.S.C. §119(e) toU.S. Provisional Application No. 61/381,048, entitled “Acknowledgmentand/or receiver recovery mechanisms for scheduled responses withinmultiple user, multiple access, and/or MIMO wireless communications,”filed Sep. 8, 2010, both of which are hereby incorporated herein byreference in their entirety and made part of the present U.S. Utilitypatent application for all purposes.

INCORPORATION BY REFERENCE

The following IEEE standards are hereby incorporated herein by referencein their entirety and are made part of the present U.S. Utility patentapplication for all purposes:

1. IEEE Std 802.11™—2007, “IEEE Standard for Informationtechnology—Telecommunications and information exchange betweensystems—Local and metropolitan area networks—Specific requirements; Part11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)Specifications,” IEEE Computer Society, IEEE Std 802.11™—2007, (Revisionof IEEE Std 802.11-1999), 1233 pages.

2. IEEE Std 802.11n™—2009, “IEEE Standard for Informationtechnology—Telecommunications and information exchange betweensystems—Local and metropolitan area networks—Specific requirements; Part11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)Specifications; Amendment 5: Enhancements for Higher Throughput,” IEEEComputer Society, IEEE Std 802.11n™—2009, (Amendment to IEEE Std802.11™—2007 as amended by IEEE Std 802.11k™—2008, IEEE Std802.11r™—2008, IEEE Std 802.11y™—2008, and IEEE Std 802.11r™—2009), 536pages.

3. IEEE P802.11ac™/D1.1, August 2011, “Draft STANDARD for InformationTechnology—Telecommunications and information exchange betweensystems—Local and metropolitan area networks—Specific requirements, Part11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)specifications, Amendment 5: Enhancements for Very High Throughput forOperation in Bands below 6 GHz,” Prepared by the 802.11 Working Group ofthe 802 Committee, 297 total pages (pp. i-xxiii, 1-274).

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The invention relates generally to communication systems; and, moreparticularly, it relates to acknowledgment and/or receiver recoverymechanisms for scheduled responses within multiple user, multipleaccess, and/or MIMO wireless communications.

2. Description of Related Art

Communication systems are known to support wireless and wire linedcommunications between wireless and/or wire lined communication devices.Such communication systems range from national and/or internationalcellular telephone systems to the Internet to point-to-point in-homewireless networks. Each type of communication system is constructed, andhence operates, in accordance with one or more communication standards.For instance, wireless communication systems may operate in accordancewith one or more standards including, but not limited to, IEEE 802.11x,Bluetooth, advanced mobile phone services (AMPS), digital AMPS, globalsystem for mobile communications (GSM), code division multiple access(CDMA), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), and/or variationsthereof.

Depending on the type of wireless communication system, a wirelesscommunication device, such as a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, etc., communicates directly orindirectly with other wireless communication devices. For directcommunications (also known as point-to-point communications), theparticipating wireless communication devices tune their receivers andtransmitters to the same channel or channels (e.g., one of the pluralityof radio frequency (RF) carriers of the wireless communication system)and communicate over that channel(s). For indirect wirelesscommunications, each wireless communication device communicates directlywith an associated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe Internet, and/or via some other wide area network.

For each wireless communication device to participate in wirelesscommunications, it includes a built-in radio transceiver (i.e., receiverand transmitter) or is coupled to an associated radio transceiver (e.g.,a station for in-home and/or in-building wireless communicationnetworks, RF modem, etc.). As is known, the receiver is coupled to theantenna and includes a low noise amplifier, one or more intermediatefrequency stages, a filtering stage, and a data recovery stage. The lownoise amplifier receives inbound RF signals via the antenna andamplifies them. The one or more intermediate frequency stages mix theamplified RF signals with one or more local oscillations to convert theamplified RF signal into baseband signals or intermediate frequency (IF)signals. The filtering stage filters the baseband signals or the IFsignals to attenuate unwanted out of band signals to produce filteredsignals. The data recovery stage recovers raw data from the filteredsignals in accordance with the particular wireless communicationstandard.

As is also known, the transmitter includes a data modulation stage, oneor more intermediate frequency stages, and a power amplifier. The datamodulation stage converts raw data into baseband signals in accordancewith a particular wireless communication standard. The one or moreintermediate frequency stages mix the baseband signals with one or morelocal oscillations to produce RF signals. The power amplifier amplifiesthe RF signals prior to transmission via an antenna.

Typically, the transmitter will include one antenna for transmitting theRF signals, which are received by a single antenna, or multiple antennae(alternatively, antennas), of a receiver. When the receiver includes twoor more antennae, the receiver will select one of them to receive theincoming RF signals. In this instance, the wireless communicationbetween the transmitter and receiver is a single-output-single-input(SISO) communication, even if the receiver includes multiple antennaethat are used as diversity antennae (i.e., selecting one of them toreceive the incoming RF signals). For SISO wireless communications, atransceiver includes one transmitter and one receiver. Currently, mostwireless local area networks (WLAN) that are IEEE 802.11, 802.11a,802.11b, or 802.11g employ SISO wireless communications.

Other types of wireless communications includesingle-input-multiple-output (SIMO), multiple-input-single-output(MISO), and multiple-input-multiple-output (MIMO). In a SIMO wirelesscommunication, a single transmitter processes data into radio frequencysignals that are transmitted to a receiver. The receiver includes two ormore antennae and two or more receiver paths. Each of the antennaereceives the RF signals and provides them to a corresponding receiverpath (e.g., LNA, down conversion module, filters, and ADCs). Each of thereceiver paths processes the received RF signals to produce digitalsignals, which are combined and then processed to recapture thetransmitted data.

For a multiple-input-single-output (MISO) wireless communication, thetransmitter includes two or more transmission paths (e.g., digital toanalog converter, filters, up-conversion module, and a power amplifier)that each converts a corresponding portion of baseband signals into RFsignals, which are transmitted via corresponding antennae to a receiver.The receiver includes a single receiver path that receives the multipleRF signals from the transmitter. In this instance, the receiver usesbeam forming to combine the multiple RF signals into one signal forprocessing.

For a multiple-input-multiple-output (MIMO) wireless communication, thetransmitter and receiver each include multiple paths. In such acommunication, the transmitter parallel processes data using a spatialand time encoding function to produce two or more streams of data. Thetransmitter includes multiple transmission paths to convert each streamof data into multiple RF signals. The receiver receives the multiple RFsignals via multiple receiver paths that recapture the streams of datautilizing a spatial and time decoding function. The recaptured streamsof data are combined and subsequently processed to recover the originaldata.

With the various types of wireless communications (e.g., SISO, MISO,SIMO, and MIMO), it would be desirable to use one or more types ofwireless communications to enhance data throughput within a WLAN. Forexample, high data rates can be achieved with MIMO communications incomparison to SISO communications.

However, most WLAN include legacy wireless communication devices (i.e.,devices that are compliant with an older version of a wirelesscommunication standard). As such, a transmitter capable of MIMO wirelesscommunications should also be backward compatible with legacy devices tofunction in a majority of existing WLANs.

Therefore, a need exists for a WLAN device that is capable of high datathroughput and is backward compatible with legacy devices.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an embodiment of a wirelesscommunication system.

FIG. 2 is a diagram illustrating an embodiment of a wirelesscommunication device.

FIG. 3 is a diagram illustrating an embodiment of a radio frequency (RF)transmitter.

FIG. 4 is a diagram illustrating an embodiment of an RF receiver.

FIG. 5 is a diagram illustrating an embodiment of a method for basebandprocessing of data.

FIG. 6 is a diagram illustrating an embodiment of a method that furtherdefines Step 120 of FIG. 5.

FIGS. 7-9 are diagrams illustrating various embodiments for encoding thescrambled data.

FIGS. 10A and 10B are diagrams illustrating embodiments of a radiotransmitter.

FIGS. 11A and 11B are diagrams illustrating embodiments of a radioreceiver.

FIG. 12 is a diagram illustrating an embodiment of an access point (AP)and multiple wireless local area network (WLAN) devices operatingaccording to one or more various aspects and/or embodiments of theinvention.

FIG. 13 is a diagram illustrating an embodiment of a wirelesscommunication device, and clusters, as may be employed for supportingcommunications with at least one additional wireless communicationdevice.

FIG. 14 is a diagram illustrating an embodiment of a wirelesscommunication system in which communications are made between variouswireless communication devices therein.

FIG. 15 is a diagram illustrating an embodiment of schedule field.

FIG. 16A, FIG. 16B, and FIG. 16C are diagrams illustrating variousembodiments of frames including a respective schedule field therein.

FIG. 17 is a diagram illustrating an embodiment of a modified request tosend (RTS) format including a schedule field therein.

FIG. 18 is a diagram illustrating an embodiment of a timing diagramshowing a schedule (SCH) frame being transmitted after a clear to send(CTS) frame.

FIG. 19 is a diagram illustrating an embodiment of a timing diagramshowing a schedule (SCH) frame being transmitted after a clear to send(CTS) frame such that the scheduling information is included in amulti-user multiple-input-multiple-output (MU-MIMO) frame (which mayinclude data therein).

FIG. 20 is a diagram illustrating an embodiment of a timing diagramshowing a schedule (SCH) frame being transmitted after a downlinkmultiple input multiple output (MU-MIMO) frame.

FIG. 21 is a diagram illustrating an embodiment of a timing diagramshowing an exchange employing a modified RTS frame.

FIG. 22 is a diagram illustrating an embodiment of a timing diagramshowing an exchange employing a schedule (SCH) frame at start.

FIG. 23 is a diagram illustrating an embodiment of a wirelesscommunication system in which recovery mechanisms may be performedbetween various wireless communication devices therein.

FIG. 24A, FIG. 24B, FIG. 25A, FIG. 25B, FIG. 26A, FIG. 26B, FIG. 27A,and FIG. 27B are diagrams illustrating embodiments of methods foroperating one or more wireless communication devices.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a diagram illustrating an embodiment of a wirelesscommunication system 10 that includes a plurality of base stationsand/or access points 12-16, a plurality of wireless communicationdevices 18-32 and a network hardware component 34. The wirelesscommunication devices 18-32 may be laptop host computers 18 and 26,personal digital assistant hosts 20 and 30, personal computer hosts 24and 32 and/or cellular telephone hosts 22 and 28. The details of anembodiment of such wireless communication devices are described ingreater detail with reference to FIG. 2.

The base stations (BSs) or access points (APs) 12-16 are operablycoupled to the network hardware 34 via local area network connections36, 38 and 40. The network hardware 34, which may be a router, switch,bridge, modem, system controller, etc., provides a wide area networkconnection 42 for the communication system 10. Each of the base stationsor access points 12-16 has an associated antenna or antenna array tocommunicate with the wireless communication devices in its area.Typically, the wireless communication devices register with a particularbase station or access point 12-14 to receive services from thecommunication system 10. For direct connections (i.e., point-to-pointcommunications), wireless communication devices communicate directly viaan allocated channel.

Typically, base stations are used for cellular telephone systems (e.g.,advanced mobile phone services (AMPS), digital AMPS, global system formobile communications (GSM), code division multiple access (CDMA), localmulti-point distribution systems (LMDS), multi-channel-multi-pointdistribution systems (MMDS), Enhanced Data rates for GSM Evolution(EDGE), General Packet Radio Service (GPRS), high-speed downlink packetaccess (HSDPA), high-speed uplink packet access (HSUPA and/or variationsthereof) and like-type systems, while access points are used for in-homeor in-building wireless networks (e.g., IEEE 802.11, Bluetooth, ZigBee,any other type of radio frequency based network protocol and/orvariations thereof). Regardless of the particular type of communicationsystem, each wireless communication device includes a built-in radioand/or is coupled to a radio. Such wireless communication devices mayoperate in accordance with the various aspects of the invention aspresented herein to enhance performance, reduce costs, reduce size,and/or enhance broadband applications.

FIG. 2 is a diagram illustrating an embodiment of a wirelesscommunication device that includes the host device 18-32 and anassociated radio 60. For cellular telephone hosts, the radio 60 is abuilt-in component. For personal digital assistants hosts, laptop hosts,and/or personal computer hosts, the radio 60 may be built-in or anexternally coupled component. For access points or base stations, thecomponents are typically housed in a single structure.

As illustrated, the host device 18-32 includes a processing module 50,memory 52, radio interface 54, input interface 58 and output interface56. The processing module 50 and memory 52 execute the correspondinginstructions that are typically done by the host device. For example,for a cellular telephone host device, the processing module 50 performsthe corresponding communication functions in accordance with aparticular cellular telephone standard.

The radio interface 54 allows data to be received from and sent to theradio 60. For data received from the radio 60 (e.g., inbound data), theradio interface 54 provides the data to the processing module 50 forfurther processing and/or routing to the output interface 56. The outputinterface 56 provides connectivity to an output display device such as adisplay, monitor, speakers, etc. such that the received data may bedisplayed. The radio interface 54 also provides data from the processingmodule 50 to the radio 60. The processing module 50 may receive theoutbound data from an input device such as a keyboard, keypad,microphone, etc. via the input interface 58 or generate the data itself.For data received via the input interface 58, the processing module 50may perform a corresponding host function on the data and/or route it tothe radio 60 via the radio interface 54.

Radio 60 includes a host interface 62, a baseband processing module 64,memory 66, a plurality of radio frequency (RF) transmitters 68-72, atransmit/receive (T/R) module 74, a plurality of antennae 82-86, aplurality of RF receivers 76-80, and a local oscillation module 100. Thebaseband processing module 64, in combination with operationalinstructions stored in memory 66, execute digital receiver functions anddigital transmitter functions, respectively. The digital receiverfunctions, as will be described in greater detail with reference to FIG.11B, include, but are not limited to, digital intermediate frequency tobaseband conversion, demodulation, constellation demapping, decoding,de-interleaving, fast Fourier transform, cyclic prefix removal, spaceand time decoding, and/or descrambling. The digital transmitterfunctions, as will be described in greater detail with reference tolater Figures, include, but are not limited to, scrambling, encoding,interleaving, constellation mapping, modulation, inverse fast Fouriertransform, cyclic prefix addition, space and time encoding, and/ordigital baseband to IF conversion. The baseband processing modules 64may be implemented using one or more processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on operationalinstructions. The memory 66 may be a single memory device or a pluralityof memory devices. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, and/or any device that storesdigital information. Note that when the processing module 64 implementsone or more of its functions via a state machine, analog circuitry,digital circuitry, and/or logic circuitry, the memory storing thecorresponding operational instructions is embedded with the circuitrycomprising the state machine, analog circuitry, digital circuitry,and/or logic circuitry.

In operation, the radio 60 receives outbound data 88 from the hostdevice via the host interface 62. The baseband processing module 64receives the outbound data 88 and, based on a mode selection signal 102,produces one or more outbound symbol streams 90. The mode selectionsignal 102 will indicate a particular mode as are illustrated in themode selection tables, which appear at the end of the detaileddiscussion. For example, the mode selection signal 102, with referenceto table 1 may indicate a frequency band of 2.4 GHz or 5 GHz, a channelbandwidth of 20 or 22 MHz (e.g., channels of 20 or 22 MHz width) and amaximum bit rate of 54 megabits-per-second. In other embodiments, thechannel bandwidth may extend up to 1.28 GHz or wider with supportedmaximum bit rates extending to 1 gigabit-per-second or greater. In thisgeneral category, the mode selection signal will further indicate aparticular rate ranging from 1 megabit-per-second to 54megabits-per-second. In addition, the mode selection signal willindicate a particular type of modulation, which includes, but is notlimited to, Barker Code Modulation, BPSK, QPSK, CCK, 16 QAM and/or 64QAM. As is further illustrated in table 1, a code rate is supplied aswell as number of coded bits per subcarrier (NBPSC), coded bits per OFDMsymbol (NCBPS), data bits per OFDM symbol (NDBPS).

The mode selection signal may also indicate a particular channelizationfor the corresponding mode which for the information in table 1 isillustrated in table 2. As shown, table 2 includes a channel number andcorresponding center frequency. The mode select signal may furtherindicate a power spectral density mask value which for table 1 isillustrated in table 3. The mode select signal may alternativelyindicate rates within table 4 that has a 5 GHz frequency band, 20 MHzchannel bandwidth and a maximum bit rate of 54 megabits-per-second. Ifthis is the particular mode select, the channelization is illustrated intable 5. As a further alternative, the mode select signal 102 mayindicate a 2.4 GHz frequency band, 20 MHz channels and a maximum bitrate of 192 megabits-per-second as illustrated in table 6. In table 6, anumber of antennae may be utilized to achieve the higher bit rates. Inthis instance, the mode select would further indicate the number ofantennae to be utilized. Table 7 illustrates the channelization for theset-up of table 6. Table 8 illustrates yet another mode option where thefrequency band is 2.4 GHz, the channel bandwidth is 20 MHz and themaximum bit rate is 192 megabits-per-second. The corresponding table 8includes various bit rates ranging from 12 megabits-per-second to 216megabits-per-second utilizing 2-4 antennae and a spatial time encodingrate as indicated. Table 9 illustrates the channelization for table 8.The mode select signal 102 may further indicate a particular operatingmode as illustrated in table 10, which corresponds to a 5 GHz frequencyband having 40 MHz frequency band having 40 MHz channels and a maximumbit rate of 486 megabits-per-second. As shown in table 10, the bit ratemay range from 13.5 megabits-per-second to 486 megabits-per-secondutilizing 1-4 antennae and a corresponding spatial time code rate. Table10 further illustrates a particular modulation scheme code rate andNBPSC values. Table 11 provides the power spectral density mask fortable 10 and table 12 provides the channelization for table 10.

It is of course noted that other types of channels, having differentbandwidths, may be employed in other embodiments without departing fromthe scope and spirit of the invention. For example, various otherchannels such as those having 80 MHz, 120 MHz, and/or 160 MHz ofbandwidth may alternatively be employed such as in accordance with IEEETask Group ac (TGac VHTL6).

The baseband processing module 64, based on the mode selection signal102 produces the one or more outbound symbol streams 90, as will befurther described with reference to FIGS. 5-9 from the output data 88.For example, if the mode selection signal 102 indicates that a singletransmit antenna is being utilized for the particular mode that has beenselected, the baseband processing module 64 will produce a singleoutbound symbol stream 90. Alternatively, if the mode select signalindicates 2, 3 or 4 antennae, the baseband processing module 64 willproduce 2, 3 or 4 outbound symbol streams 90 corresponding to the numberof antennae from the output data 88.

Depending on the number of outbound streams 90 produced by the basebandmodule 64, a corresponding number of the RF transmitters 68-72 will beenabled to convert the outbound symbol streams 90 into outbound RFsignals 92. The implementation of the RF transmitters 68-72 will befurther described with reference to FIG. 3. The transmit/receive module74 receives the outbound RF signals 92 and provides each outbound RFsignal to a corresponding antenna 82-86.

When the radio 60 is in the receive mode, the transmit/receive module 74receives one or more inbound RF signals via the antennae 82-86. The T/Rmodule 74 provides the inbound RF signals 94 to one or more RF receivers76-80. The RF receiver 76-80, which will be described in greater detailwith reference to FIG. 4, converts the inbound RF signals 94 into acorresponding number of inbound symbol streams 96. The number of inboundsymbol streams 96 will correspond to the particular mode in which thedata was received (recall that the mode may be any one of the modesillustrated in tables 1-12). The baseband processing module 64 receivesthe inbound symbol streams 90 and converts them into inbound data 98,which is provided to the host device 18-32 via the host interface 62.

In one embodiment of radio 60 it includes a transmitter and a receiver.The transmitter may include a MAC module, a PLCP module, and a PMDmodule. The Medium Access Control (MAC) module, which may be implementedwith the processing module 64, is operably coupled to convert a MACService Data Unit (MSDU) into a MAC Protocol Data Unit (MPDU) inaccordance with a WLAN protocol. The Physical Layer ConvergenceProcedure (PLCP) Module, which may be implemented in the processingmodule 64, is operably coupled to convert the MPDU into a PLCP ProtocolData Unit (PPDU) in accordance with the WLAN protocol. The PhysicalMedium Dependent (PMD) module is operably coupled to convert the PPDUinto a plurality of radio frequency (RF) signals in accordance with oneof a plurality of operating modes of the WLAN protocol, wherein theplurality of operating modes includes multiple input and multiple outputcombinations.

An embodiment of the Physical Medium Dependent (PMD) module, which willbe described in greater detail with reference to FIGS. 10A and 10B,includes an error protection module, a demultiplexing module, and aplurality of direction conversion modules. The error protection module,which may be implemented in the processing module 64, is operablycoupled to restructure a PPDU (PLCP (Physical Layer ConvergenceProcedure) Protocol Data Unit) to reduce transmission errors producingerror protected data. The demultiplexing module is operably coupled todivide the error protected data into a plurality of error protected datastreams The plurality of direct conversion modules is operably coupledto convert the plurality of error protected data streams into aplurality of radio frequency (RF) signals.

As one of average skill in the art will appreciate, the wirelesscommunication device of FIG. 2 may be implemented using one or moreintegrated circuits. For example, the host device may be implemented onone integrated circuit, the baseband processing module 64 and memory 66may be implemented on a second integrated circuit, and the remainingcomponents of the radio 60, less the antennae 82-86, may be implementedon a third integrated circuit. As an alternate example, the radio 60 maybe implemented on a single integrated circuit. As yet another example,the processing module 50 of the host device and the baseband processingmodule 64 may be a common processing device implemented on a singleintegrated circuit. Further, the memory 52 and memory 66 may beimplemented on a single integrated circuit and/or on the same integratedcircuit as the common processing modules of processing module 50 and thebaseband processing module 64.

FIG. 3 is a diagram illustrating an embodiment of a radio frequency (RF)transmitter 68-72, or RF front-end, of the WLAN transmitter. The RFtransmitter 68-72 includes a digital filter and up-sampling module 75, adigital-to-analog conversion module 77, an analog filter 79, andup-conversion module 81, a power amplifier 83 and a RF filter 85. Thedigital filter and up-sampling module 75 receives one of the outboundsymbol streams 90 and digitally filters it and then up-samples the rateof the symbol streams to a desired rate to produce the filtered symbolstreams 87. The digital-to-analog conversion module 77 converts thefiltered symbols 87 into analog signals 89. The analog signals mayinclude an in-phase component and a quadrature component.

The analog filter 79 filters the analog signals 89 to produce filteredanalog signals 91. The up-conversion module 81, which may include a pairof mixers and a filter, mixes the filtered analog signals 91 with alocal oscillation 93, which is produced by local oscillation module 100,to produce high frequency signals 95. The frequency of the highfrequency signals 95 corresponds to the frequency of the outbound RFsignals 92.

The power amplifier 83 amplifies the high frequency signals 95 toproduce amplified high frequency signals 97. The RF filter 85, which maybe a high frequency band-pass filter, filters the amplified highfrequency signals 97 to produce the desired output RF signals 92.

As one of average skill in the art will appreciate, each of the radiofrequency transmitters 68-72 will include a similar architecture asillustrated in FIG. 3 and further include a shut-down mechanism suchthat when the particular radio frequency transmitter is not required, itis disabled in such a manner that it does not produce interferingsignals and/or noise.

FIG. 4 is a diagram illustrating an embodiment of an RF receiver. Thismay depict any one of the RF receivers 76-80. In this embodiment, eachof the RF receivers 76-80 includes an RF filter 101, a low noiseamplifier (LNA) 103, a programmable gain amplifier (PGA) 105, adown-conversion module 107, an analog filter 109, an analog-to-digitalconversion module 111 and a digital filter and down-sampling module 113.The RF filter 101, which may be a high frequency band-pass filter,receives the inbound RF signals 94 and filters them to produce filteredinbound RF signals. The low noise amplifier 103 amplifies the filteredinbound RF signals 94 based on a gain setting 115 and provides theamplified signals to the programmable gain amplifier 105. Theprogrammable gain amplifier further amplifies the inbound RF signals 94before providing them to the down-conversion module 107.

The down-conversion module 107 includes a pair of mixers, a summationmodule, and a filter to mix the inbound RF signals with a localoscillation (LO) signal 117 that is provided by the local oscillationmodule 100 to produce analog baseband signals. The analog filter 109filters the analog baseband signals and provides them to theanalog-to-digital conversion module 111 which converts them into adigital signal. The digital filter and down-sampling module 113 filtersthe digital signals and then adjusts the sampling rate to produce thedigital samples (corresponding to the inbound symbol streams 96).

FIG. 5 is a diagram illustrating an embodiment of a method for basebandprocessing of data. This diagram shows a method for converting outbounddata 88 into one or more outbound symbol streams 90 by the basebandprocessing module 64. The process begins at Step 110 where the basebandprocessing module receives the outbound data 88 and a mode selectionsignal 102. The mode selection signal may indicate any one of thevarious modes of operation as indicated in tables 1-12. The process thenproceeds to Step 112 where the baseband processing module scrambles thedata in accordance with a pseudo random sequence to produce scrambleddata. Note that the pseudo random sequence may be generated from afeedback shift register with the generator polynomial of S(x)=x⁷+x⁴+1.

The process then proceeds to Step 114 where the baseband processingmodule selects one of a plurality of encoding modes based on the modeselection signal. The process then proceeds to Step 116 where thebaseband processing module encodes the scrambled data in accordance witha selected encoding mode to produce encoded data. The encoding may bedone utilizing any one or more a variety of coding schemes (e.g.,convolutional coding, Reed-Solomon (RS) coding, turbo coding, turbotrellis coded modulation (TTCM) coding, LDPC (Low Density Parity Check)coding, etc.).

The process then proceeds to Step 118 where the baseband processingmodule determines a number of transmit streams based on the mode selectsignal. For example, the mode select signal will select a particularmode which indicates that 1, 2, 3, 4 or more antennae may be utilizedfor the transmission. Accordingly, the number of transmit streams willcorrespond to the number of antennae indicated by the mode selectsignal. The process then proceeds to Step 120 where the basebandprocessing module converts the encoded data into streams of symbols inaccordance with the number of transmit streams in the mode selectsignal. This step will be described in greater detail with reference toFIG. 6.

FIG. 6 is a diagram illustrating an embodiment of a method that furtherdefines Step 120 of FIG. 5. This diagram shows a method performed by thebaseband processing module to convert the encoded data into streams ofsymbols in accordance with the number of transmit streams and the modeselect signal. Such processing begins at Step 122 where the basebandprocessing module interleaves the encoded data over multiple symbols andsubcarriers of a channel to produce interleaved data. In general, theinterleaving process is designed to spread the encoded data overmultiple symbols and transmit streams. This allows improved detectionand error correction capability at the receiver. In one embodiment, theinterleaving process will follow the IEEE 802.11(a) or (g) standard forbackward compatible modes. For higher performance modes (e.g., IEEE802.11(n), the interleaving will also be done over multiple transmitpaths or streams.

The process then proceeds to Step 124 where the baseband processingmodule demultiplexes the interleaved data into a number of parallelstreams of interleaved data. The number of parallel streams correspondsto the number of transmit streams, which in turn corresponds to thenumber of antennae indicated by the particular mode being utilized. Theprocess then continues to Steps 126 and 128, where for each of theparallel streams of interleaved data, the baseband processing modulemaps the interleaved data into a quadrature amplitude modulated (QAM)symbol to produce frequency domain symbols at Step 126. At Step 128, thebaseband processing module converts the frequency domain symbols intotime domain symbols, which may be done utilizing an inverse fast Fouriertransform. The conversion of the frequency domain symbols into the timedomain symbols may further include adding a cyclic prefix to allowremoval of intersymbol interference at the receiver. Note that thelength of the inverse fast Fourier transform and cyclic prefix aredefined in the mode tables of tables 1-12. In general, a 64-pointinverse fast Fourier transform is employed for 20 MHz channels and128-point inverse fast Fourier transform is employed for 40 MHzchannels.

The process then proceeds to Step 130 where the baseband processingmodule space and time encodes the time domain symbols for each of theparallel streams of interleaved data to produce the streams of symbols.In one embodiment, the space and time encoding may be done by space andtime encoding the time domain symbols of the parallel streams ofinterleaved data into a corresponding number of streams of symbolsutilizing an encoding matrix. Alternatively, the space and time encodingmay be done by space and time encoding the time domain symbols ofM-parallel streams of interleaved data into P-streams of symbolsutilizing the encoding matrix, where P=2M. In one embodiment theencoding matrix may comprise a form of:

$\quad\begin{bmatrix}C_{1} & C_{2} & C_{3} & C_{4} & \ldots & C_{{2\; M} - 1} & C_{2\; M} \\{- C_{2}^{*}} & C_{1}^{*} & {- C_{4}^{*}} & C_{3}^{*} & \ldots & {- C_{2\; M}^{*}} & C_{{2\; M} - 1}\end{bmatrix}$

The number of rows of the encoding matrix corresponds to M and thenumber of columns of the encoding matrix corresponds to P. Theparticular symbol values of the constants within the encoding matrix maybe real or imaginary numbers.

FIGS. 7-9 are diagrams illustrating various embodiments for encoding thescrambled data.

FIG. 7 is a diagram of one method that may be utilized by the basebandprocessing module to encode the scrambled data at Step 116 of FIG. 5. Inthis method, the encoding of FIG. 7 may include an optional Step 144where the baseband processing module may optionally perform encodingwith an outer Reed-Solomon (RS) code to produce RS encoded data. It isnoted that Step 144 may be conducted in parallel with Step 140 describedbelow.

Also, the process continues at Step 140 where the baseband processingmodule performs a convolutional encoding with a 64 state code andgenerator polynomials of G₀=133₈ and G₁=171₈ on the scrambled data (thatmay or may not have undergone RS encoding) to produce convolutionalencoded data. The process then proceeds to Step 142 where the basebandprocessing module punctures the convolutional encoded data at one of aplurality of rates in accordance with the mode selection signal toproduce the encoded data. Note that the puncture rates may include ½, ⅔and/or ¾, or any rate as specified in tables 1-12. Note that, for aparticular, mode, the rate may be selected for backward compatibilitywith IEEE 802.11(a), IEEE 802.11(g), or IEEE 802.11(n) raterequirements.

FIG. 8 is a diagram of another encoding method that may be utilized bythe baseband processing module to encode the scrambled data at Step 116of FIG. 5. In this embodiment, the encoding of FIG. 8 may include anoptional Step 148 where the baseband processing module may optionallyperform encoding with an outer RS code to produce RS encoded data. It isnoted that Step 148 may be conducted in parallel with Step 146 describedbelow.

The method then continues at Step 146 where the baseband processingmodule encodes the scrambled data (that may or may not have undergone RSencoding) in accordance with a complimentary code keying (CCK) code toproduce the encoded data. This may be done in accordance with IEEE802.11(b) specifications, IEEE 802.11(g), and/or IEEE 802.11(n)specifications.

FIG. 9 is a diagram of yet another method for encoding the scrambleddata at Step 116, which may be performed by the baseband processingmodule. In this embodiment, the encoding of FIG. 9 may include anoptional Step 154 where the baseband processing module may optionallyperform encoding with an outer RS code to produce RS encoded data.

Then, in some embodiments, the process continues at Step 150 where thebaseband processing module performs LDPC (Low Density Parity Check)coding on the scrambled data (that may or may not have undergone RSencoding) to produce LDPC coded bits. Alternatively, the Step 150 mayoperate by performing convolutional encoding with a 256 state code andgenerator polynomials of G₀=561₈ and G₁=753₈ on the scrambled data thescrambled data (that may or may not have undergone RS encoding) toproduce convolutional encoded data. The process then proceeds to Step152 where the baseband processing module punctures the convolutionalencoded data at one of the plurality of rates in accordance with a modeselection signal to produce encoded data. Note that the puncture rate isindicated in the tables 1-12 for the corresponding mode.

The encoding of FIG. 9 may further include the optional Step 154 wherethe baseband processing module combines the convolutional encoding withan outer Reed Solomon code to produce the convolutional encoded data.

FIGS. 10A and 10B are diagrams illustrating embodiments of a radiotransmitter. This may involve the PMD module of a WLAN transmitter. InFIG. 10A, the baseband processing is shown to include a scrambler 172,channel encoder 174, interleaver 176, demultiplexer 170, a plurality ofsymbol mappers 180-184, a plurality of inverse fast Fourier transform(IFFT)/cyclic prefix addition modules 186-190 and a space/time encoder192. The baseband portion of the transmitter may further include a modemanager module 175 that receives the mode selection signal 173 andproduces settings 179 for the radio transmitter portion and produces therate selection 171 for the baseband portion. In this embodiment, thescrambler 172, the channel encoder 174, and the interleaver 176 comprisean error protection module. The symbol mappers 180-184, the plurality ofIFFT/cyclic prefix modules 186-190, the space time encoder 192 comprisea portion of the digital baseband processing module.

In operations, the scrambler 172 adds (e.g., in a Galois Finite Field(GF2)) a pseudo random sequence to the outbound data bits 88 to make thedata appear random. A pseudo random sequence may be generated from afeedback shift register with the generator polynomial of S(x)=x⁷+x⁴+1 toproduce scrambled data. The channel encoder 174 receives the scrambleddata and generates a new sequence of bits with redundancy. This willenable improved detection at the receiver. The channel encoder 174 mayoperate in one of a plurality of modes. For example, for backwardcompatibility with IEEE 802.11(a) and IEEE 802.11(g), the channelencoder has the form of a rate ½ convolutional encoder with 64 statesand a generator polynomials of G₀=133₈ and G₁=171₈. The output of theconvolutional encoder may be punctured to rates of ½, ⅔, and ¾ accordingto the specified rate tables (e.g., tables 1-12). For backwardcompatibility with IEEE 802.11(b) and the CCK modes of IEEE 802.11(g),the channel encoder has the form of a CCK code as defined in IEEE802.11(b). For higher data rates (such as those illustrated in tables 6,8 and 10), the channel encoder may use the same convolution encoding asdescribed above or it may use a more powerful code, including aconvolutional code with more states, any one or more of the varioustypes of error correction codes (ECCs) mentioned above (e.g., RS, LDPC,turbo, TTCM, etc.) a parallel concatenated (turbo) code and/or a lowdensity parity check (LDPC) block code. Further, any one of these codesmay be combined with an outer Reed Solomon code. Based on a balancing ofperformance, backward compatibility and low latency, one or more ofthese codes may be optimal. Note that the concatenated turbo encodingand low density parity check will be described in greater detail withreference to subsequent Figures.

The interleaver 176 receives the encoded data and spreads it overmultiple symbols and transmit streams. This allows improved detectionand error correction capabilities at the receiver. In one embodiment,the interleaver 176 will follow the IEEE 802.11(a) or (g) standard inthe backward compatible modes. For higher performance modes (e.g., suchas those illustrated in tables 6, 8 and 10), the interleaver willinterleave data over multiple transmit streams. The demultiplexer 170converts the serial interleave stream from interleaver 176 intoM-parallel streams for transmission.

Each symbol mapper 180-184 receives a corresponding one of theM-parallel paths of data from the demultiplexer. Each symbol mapper180-182 lock maps bit streams to quadrature amplitude modulated QAMsymbols (e.g., BPSK, QPSK, 16 QAM, 64 QAM, 256 QAM, etc.) according tothe rate tables (e.g., tables 1-12). For IEEE 802.11(a) backwardcompatibility, double Gray coding may be used.

The map symbols produced by each of the symbol mappers 180-184 areprovided to the IFFT/cyclic prefix addition modules 186-190, whichperforms frequency domain to time domain conversions and adds a prefix,which allows removal of inter-symbol interference at the receiver. Notethat the length of the IFFT and cyclic prefix are defined in the modetables of tables 1-12. In general, a 64-point IFFT will be used for 20MHz channels and 128-point IFFT will be used for 40 MHz channels.

The space/time encoder 192 receives the M-parallel paths of time domainsymbols and converts them into P-output symbols. In one embodiment, thenumber of M-input paths will equal the number of P-output paths. Inanother embodiment, the number of output paths P will equal 2M paths.For each of the paths, the space/time encoder multiples the inputsymbols with an encoding matrix that has the form of

$\quad{\begin{bmatrix}C_{1} & C_{2} & C_{3} & C_{4} & \ldots & C_{{2\; M} - 1} & C_{2\; M} \\{- C_{2}^{*}} & C_{1}^{*} & {- C_{4}^{*}} & C_{3}^{*} & \ldots & {- C_{2\; M}^{*}} & C_{{2\; M} - 1}\end{bmatrix}.}$

The rows of the encoding matrix correspond to the number of input pathsand the columns correspond to the number of output paths.

FIG. 10B illustrates the radio portion of the transmitter that includesa plurality of digital filter/up-sampling modules 194-198,digital-to-analog conversion modules 200-204, analog filters 206-216,I/Q modulators 218-222, RF amplifiers 224-228, RF filters 230-234 andantennae 236-240. The P-outputs from the space/time encoder 192 arereceived by respective digital filtering/up-sampling modules 194-198. Inone embodiment, the digital filters/up sampling modules 194-198 are partof the digital baseband processing module and the remaining componentscomprise the plurality of RF front-ends. In such an embodiment, thedigital baseband processing module and the RF front end comprise adirect conversion module.

In operation, the number of radio paths that are active correspond tothe number of P-outputs. For example, if only one P-output path isgenerated, only one of the radio transmitter paths will be active. Asone of average skill in the art will appreciate, the number of outputpaths may range from one to any desired number.

The digital filtering/up-sampling modules 194-198 filter thecorresponding symbols and adjust the sampling rates to correspond withthe desired sampling rates of the digital-to-analog conversion modules200-204. The digital-to-analog conversion modules 200-204 convert thedigital filtered and up-sampled signals into corresponding in-phase andquadrature analog signals. The analog filters 206-214 filter thecorresponding in-phase and/or quadrature components of the analogsignals, and provide the filtered signals to the corresponding I/Qmodulators 218-222. The I/Q modulators 218-222 based on a localoscillation, which is produced by a local oscillator 100, up-convertsthe I/Q signals into radio frequency signals.

The RF amplifiers 224-228 amplify the RF signals which are thensubsequently filtered via RF filters 230-234 before being transmittedvia antennae 236-240.

FIGS. 11A and 11B are diagrams illustrating embodiments of a radioreceiver (as shown by reference numeral 250). These diagrams illustratea schematic block diagram of another embodiment of a receiver. FIG. 11Aillustrates the analog portion of the receiver which includes aplurality of receiver paths. Each receiver path includes an antenna, RFfilters 252-256, low noise amplifiers 258-262, I/Q demodulators 264-268,analog filters 270-280, analog-to-digital converters 282-286 and digitalfilters and down-sampling modules 288-290.

In operation, the antennae receive inbound RF signals, which areband-pass filtered via the RF filters 252-256. The corresponding lownoise amplifiers 258-262 amplify the filtered signals and provide themto the corresponding I/Q demodulators 264-268. The I/Q demodulators264-268, based on a local oscillation, which is produced by localoscillator 100, down-converts the RF signals into baseband in-phase andquadrature analog signals.

The corresponding analog filters 270-280 filter the in-phase andquadrature analog components, respectively. The analog-to-digitalconverters 282-286 convert the in-phase and quadrature analog signalsinto a digital signal. The digital filtering and down-sampling modules288-290 filter the digital signals and adjust the sampling rate tocorrespond to the rate of the baseband processing, which will bedescribed in FIG. 11B.

FIG. 11B illustrates the baseband processing of a receiver. The basebandprocessing includes a space/time decoder 294, a plurality of fastFourier transform (FFT)/cyclic prefix removal modules 296-300, aplurality of symbol demapping modules 302-306, a multiplexer 308, adeinterleaver 310, a channel decoder 312, and a descramble module 314.The baseband processing module may further include a mode managingmodule 175, which produces rate selections 171 and settings 179 based onmode selections 173. The space/time decoding module 294, which performsthe inverse function of space/time encoder 192, receives P-inputs fromthe receiver paths and produce M-output paths. The M-output paths areprocessed via the FFT/cyclic prefix removal modules 296-300 whichperform the inverse function of the IFFT/cyclic prefix addition modules186-190 to produce frequency domain symbols.

The symbol demapping modules 302-306 convert the frequency domainsymbols into data utilizing an inverse process of the symbol mappers180-184. The multiplexer 308 combines the demapped symbol streams into asingle path.

The deinterleaver 310 deinterleaves the single path utilizing an inversefunction of the function performed by interleaver 176. The deinterleaveddata is then provided to the channel decoder 312 which performs theinverse function of channel encoder 174. The descrambler 314 receivesthe decoded data and performs the inverse function of scrambler 172 toproduce the inbound data 98.

FIG. 12 is a diagram illustrating an embodiment of an access point (AP)and multiple wireless local area network (WLAN) devices operatingaccording to one or more various aspects and/or embodiments of theinvention. The AP point 1200 may compatible with any number ofcommunication protocols and/or standards, e.g., IEEE 802.11(a), IEEE802.11(b), IEEE 802.11(g), IEEE 802.11(n), as well as in accordance withvarious aspects of invention. According to certain aspects of thepresent invention, the AP supports backwards compatibility with priorversions of the IEEE 802.11x standards as well. According to otheraspects of the present invention, the AP 1200 supports communicationswith the WLAN devices 1202, 1204, and 1206 with channel bandwidths, MIMOdimensions, and at data throughput rates unsupported by the prior IEEE802.11x operating standards. For example, the access point 1200 and WLANdevices 1202, 1204, and 1206 may support channel bandwidths from thoseof prior version devices and from 40 MHz to 1.28 GHz and above. Theaccess point 1200 and WLAN devices 1202, 1204, and 1206 support MIMOdimensions to 4×4 and greater. With these characteristics, the accesspoint 1200 and WLAN devices 1202, 1204, and 1206 may support datathroughput rates to 1 GHz and above.

The AP 1200 supports simultaneous communications with more than one ofthe WLAN devices 1202, 1204, and 1206. Simultaneous communications maybe serviced via OFDM tone allocations (e.g., certain number of OFDMtones in a given cluster), MIMO dimension multiplexing, or via othertechniques. With some simultaneous communications, the AP 1200 mayallocate one or more of the multiple antennae thereof respectively tosupport communication with each WLAN device 1202, 1204, and 1206, forexample.

Further, the AP 1200 and WLAN devices 1202, 1204, and 1206 are backwardscompatible with the IEEE 802.11 (a), (b), (g), and (n) operatingstandards. In supporting such backwards compatibility, these devicessupport signal formats and structures that are consistent with theseprior operating standards.

Generally, communications as described herein may be targeted forreception by a single receiver or for multiple individual receivers(e.g. via multi-user multiple input multiple output (MU-MIMO), and/orOFDMA transmissions, which are different than single transmissions witha multi-receiver address). For example, a single OFDMA transmission usesdifferent tones or sets of tones (e.g., clusters or channels) to senddistinct sets of information, each set of set of information transmittedto one or more receivers simultaneously in the time domain. Again, anOFDMA transmission sent to one user is equivalent to an OFDMtransmission (e.g., OFDM may be viewed as being a subset of OFDMA). Asingle MU-MIMO transmission may include spatially-diverse signals over acommon set of tones, each containing distinct information and eachtransmitted to one or more distinct receivers. Some single transmissionsmay be a combination of OFDMA and MU-MIMO. Multi-user (MU), as describedherein, may be viewed as being multiple users sharing at least onecluster (e.g., at least one channel within at least one band) at a sametime.

MIMO transceivers illustrated may include SISO, SIMO, and MISOtransceivers. The clusters employed for such communications (e.g., OFDMAcommunications) may be continuous (e.g., adjacent to one another) ordiscontinuous (e.g., separated by a guard interval of band gap).Transmissions on different OFDMA clusters may be simultaneous ornon-simultaneous. Such wireless communication devices as describedherein may be capable of supporting communications via a single clusteror any combination thereof. Legacy users and new version users (e.g.,TGac MU-MIMO, OFDMA, MU-MIMO/OFDMA, etc.) may share bandwidth at a giventime or they can be scheduled at different times for certainembodiments. Such a MU-MIMO/OFDMA transmitter (e.g., an AP or a STA) maytransmit packets to more than one receiving wireless communicationdevice (e.g., STA) on the same cluster (e.g., at least one channelwithin at least one band) in a single aggregated packet (such as beingtime multiplexed). In such an instance, channel training may be requiredfor all communication links to the respective receiving wirelesscommunication devices (e.g., STAs).

FIG. 13 is a diagram illustrating an embodiment of a wirelesscommunication device, and clusters, as may be employed for supportingcommunications with at least one additional wireless communicationdevice. Generally speaking, a cluster may be viewed as a depiction ofthe mapping of tones, such as for an OFDM symbol, within or among one ormore channels (e.g., sub-divided portions of the spectrum) that may besituated in one or more bands (e.g., portions of the spectrum separatedby relatively larger amounts). As an example, various channels of 20 MHzmay be situated within or centered around a 5 GHz band. The channelswithin any such band may be continuous (e.g., adjacent to one another)or discontinuous (e.g., separated by some guard interval or band gap).Oftentimes, one or more channels may be situated within a given band,and different bands need not necessarily have a same number of channelstherein. Again, a cluster may generally be understood as any combinationone or more channels among one or more bands.

The wireless communication device of this diagram may be of any of thevarious types and/or equivalents described herein (e.g., AP, WLANdevice, or other wireless communication device including, though notlimited to, any of those depicted in FIG. 1, etc.). The wirelesscommunication device includes multiple antennae from which one or moresignals may be transmitted to one or more receiving wirelesscommunication devices and/or received from one or more other wirelesscommunication devices.

Such clusters may be used for transmissions of signals via various oneor more selected antennae. For example, different clusters are shown asbeing used to transmit signals respectively using different one or moreantennae.

Also, it is noted that, with respect to certain embodiments, generalnomenclature may be employed wherein a transmitting wirelesscommunication device (e.g., such as being an Access point (AP), or awireless station (STA) operating as an ‘AP’ with respect to other STAs)initiates communications, and/or operates as a network controller typeof wireless communication device, with respect to a number of other,receiving wireless communication devices (e.g., such as being STAs), andthe receiving wireless communication devices (e.g., such as being STAs)responding to and cooperating with the transmitting wirelesscommunication device in supporting such communications. Of course, whilethis general nomenclature of transmitting wireless communicationdevice(s) and receiving wireless communication device(s) may be employedto differentiate the operations as performed by such different wirelesscommunication devices within a communication system, all such wirelesscommunication devices within such a communication system may of coursesupport bi-directional communications to and from other wirelesscommunication devices within the communication system. In other words,the various types of transmitting wireless communication device(s) andreceiving wireless communication device(s) may all supportbi-directional communications to and from other wireless communicationdevices within the communication system. Generally speaking, suchcapability, functionality, operations, etc. as described herein may beapplied to any wireless communication device.

FIG. 14 is a diagram illustrating an embodiment of a wirelesscommunication system in which communications are made between variouswireless communication devices therein. Various mechanisms are describedherein may be employed for scheduling communications between variouswireless communication devices within a multi-user (MU) environment.

In some instance, data transmissions may be targeted for reception bymultiple individual receiving wireless communication devices (e.g.,STAs). Such communications may be MU-MIMO and/or OFDMA transmissions.The transmitter of such a frame may generally be referred to amulti-user transmitter (MU-TXer) such as a transmitting wirelesscommunication device (e.g., AP or a STA). Each intended recipient of atleast a portion of such a frame may generally be referred to amulti-user receiver (MU-RXer) such as a receiving wireless communicationdevice (e.g., STA).

The multi-user packet may be any one or combination of data, channelsounding, control or management frames, etc. The intended MU-RXers ofthe MU-MIMO or OFDMA (or combination thereof) transmission need torespond to the reception of information with some form of response(often such as requested by the transmitting wireless communicationdevice). Some examples of responses may include acknowledgements (ACK)or block acknowledgements (BAs), feedback, and/or any other types ofresponses. In any of various diagrams and/or embodiments herein, whenany one such type of response is employed therein, an alternativeembodiment or variant may be implemented using another type of responsewithout departing from the scope and spirit of the invention. Forexample, with respect to different acknowledgement types, some examplesof acknowledgments (ACKs) may be either a single acknowledgement or ablock acknowledgement. Various response schemes may be operated inaccordance with various principles presented herein including slotted,polled, and scheduled response schemes.

A MU-TXer may employ MU-MIMO and/or OFDMA training exchanges toestablish data transmission operational parameters. These trainingexchanges require the transmission of feedback from the MU-RXer. Thefeedback is sent as a response to MU-MIMO/OFDMA training. The feedbackcan be sent using any of various response schemes including slotted,polled, and scheduled feedback.

Mechanisms by which scheduling information may be conveyed from atransmitting wireless communication device (e.g., AP) to a number ofreceiving wireless communication devices (e.g., STAs) are presentedherein.

For the scheduled response scheme, the MU-RXer response transmission issent according to a schedule. For example, following a downlink (DL)MU-MIMO transmission, the MU-RXer STAs each respond in turn. That is tosay, each receiving wireless communication device (e.g., STA) respondsaccording to a particular schedule. For example, such as schedule mayindicate the respective order by which the respective receiving wirelesscommunication devices (e.g., STAs) are to provide their respectiveresponses to a transmitting wireless communication device (e.g., AP).The time duration allocated to each of the respective receiving wirelesscommunication devices (e.g., STAs) need not necessarily be the same. Forexample, a first time duration may be allocated for a first of thereceiving wireless communication devices (e.g., STAs) to provide itsrespective response, while a second time duration may be allocated for asecond of the receiving wireless communication devices (e.g., STAs) toprovide its respective response, and so on. Also, the respective clusterassignment for each respective one of the receiving wirelesscommunication devices (e.g., STAs) may be provided within suchscheduling information that is included within a signal (e.g., amulti-user packet, a downlink communication, etc.) provided from atransmitting wireless communication device to the respective receivingwireless communication devices. If desired, the different respectiveresponses may be directed to be provided via different respectiveclusters. For example, a first cluster may be allocated for a first ofthe receiving wireless communication devices (e.g., STAs) to provide itsrespective response, while a second cluster may be allocated for asecond of the receiving wireless communication devices (e.g., STAs) toprovide its respective response, and so on.

The following methodologies may be used to carry scheduled informationto the receiving stations. A frame may be included with responseschedule information in the DL MU-MIMO packet (schedule (SCH) frame). Amulti-cast may be transmitted such that is that carries the responseschedule information to the participating MU-RXer stations.

Response schedule information may be including within a modified formatof the request to send (RTS) frame that precedes the DL MU-MIMOtransmission and which becomes part of the complete sequence of framesin the exchange.

A schedule (SCH) frame may be used to carry the scheduled timinginformation. An individual SCH frame may be used for each MU MU-RXer,containing scheduling information specific for that MU-RXer. The SCHframe can be aggregated in an aggregated MAC data protocol unit (A-MPDU)for each MU-RXer. There may be a distinct SCH frame per MU-RXer. The SCHframe may be a new Control Type and Subtype frame containing thefollowing fields: FC, DUR, RA, TA, 2-octet schedule information for thisRA (so as to include a relative timing point from end of MU-DL PPDU).

FIG. 15 is a diagram illustrating an embodiment of schedule field. Amulticast frame may be used to carry scheduling information in DLMU-MIMO. A multi-cast recipient address (RA) may be used for this frame.

A MU scheduling field (e.g., shown as SCH or SCHED) is included in themulticast frame's body to carry schedule time for each MU-RXer. Such aMU scheduling field is has the number of stations plus AID or MACaddress of each MU-RXer followed by two octets of timing information foreach MU-RXer (ST_(N) field). One or more pad bits may filled is added atthe end of MU scheduling field to make the total size an integermultiple of octets. This PAD field contains a variable number of bits,and may include as few as 0 bits.

The multicast frame may be transmitted after the DL MU-MIMO frame;alternatively, the multicast frame may be transmitted before the DLMU-MIMO frame (e.g., between a clear to send (CTS) and the DL-MU-MIMOframe).

The multicast frame may be a new control subtype, or a new managementframe. Alternatively, the field may be included in the body of anexisting frame (e.g., an Action frame).

A request to send (RTS) frame may be modified to carry the MU schedulinginformation. For example, MU scheduling information may be aggregatedwithin RTS.

A MU-RXer may use the scheduled information in RTS. For example, thismay be performed if the CTS and DL MU-MIMO packet is receivedsuccessfully. Alternatively, this may be performed if CTS is notreceived and/or DL MU-MIMO packet is not received successfully (e.g.,frame check sequence (FCS) failure) but the MU-RXer detects the DLMU-MIMO packet as having been transmitted from same MU TXer that sentthe RTS. The MAC address in DL MU-MIMO packet may be used the packet torealize this packet is addressed to the MU-RXer. The timing of the DLMU-MIMO packet may be used to verify the DL MU-MIMO packet istransmitted from same MU-TXer.

FIG. 16A, FIG. 16B, and FIG. 16C are diagrams illustrating variousembodiments of frames including a respective schedule field therein. Aschedule (e.g., shown as SCH or SCHED) frame is a frame that includes,in one manner or another, scheduling information for use in DL MU-MIMO.Such scheduling information may be a separate and independent frame orit may be included in some other type of frame.

For example, a multi-cast RA may be used for SCH frame.

An MU scheduling field (SCHED) (i.e., a field within a frame) isincluded in the SCH frame's body to carry schedule time for eachMU-RXer. Such a MU scheduling field may be implemented in accordancewith the aspects presented herein.

In some embodiments, such as with respect to FIG. 16A, a SCH frame maybe a new control subtype: FC contains TYPE=Control, Subtype=SCH (e.g.subtype uses any currently reserved subtype value for Control Type).

In even other embodiments, such as with respect to FIG. 16B, a SCH framemay be a new type of management frame: FC contains TYPE=Management,Subtype=SCH (e.g. subtype uses any currently reserved subtype value forManagement Type).

In yet other embodiments, such as with respect to FIG. 16C, a SCH framemay be an existing management frame. As one example, the SCHED field maybe included in the body of an Action frame. Alternatively, the FC may beimplemented to contain Type=Management, Subtype=Action. The frame bodymay be implemented to contain Category=HT or other existing category, ora new category, e.g. VHT. The frame body may be implemented to containAction=SCHEDULE (new value for action for any category).

Any of these various types of frames may also be sent as uni-castwithout departing from the scope and spirit of the invention.

FIG. 17 is a diagram illustrating an embodiment of a modified request tosend (RTS) format including a schedule field therein. The fields includeare as described below:

FC, DUR, RA, TA (these are the same as fields in the IEEE 802.11 RTSframe with the same name)

FCS₁—this being the same as FCS field in the IEEE 802.11 RTS frame

NU=Number of Users (e.g., using 3 bits as in a previous embodiment)

AID_(N)=AID of Nth MU-RXer (e.g., using 14 bits as in a previousembodiment)

ST_(N)=Schedule Time information (e.g., using 16 bits as in a previousembodiment)

PAD (e.g., using as many bits as are needed in order to make total countof bits in the frame equal an integer multiple of eight, may be as smallas ZERO bits)

It is noted that while certain embodiments herein are described usingspecific numbers of bits for certain respective fields within a givenframe, it is generally noted that any desired number of bits mayalternatively be used for different respective fields. For example, whenmore than eight users are desired to be indicated, the number of bitsfor the field NU may be increased. Also, it is noted that the scheduletime information fields need not necessarily be uniform. For example,different respective time durations may be specified within differentrespective schedule time information fields. The order in which therespective AID and ST_(x) fields occur within frame will indicate therespective order by which the receiving wireless communication devicesare to provide their respective responses.

FIG. 18 is a diagram illustrating an embodiment of a timing diagramshowing a schedule (SCH) frame being transmitted after a clear to send(CTS) frame. A SCH frame is sent between a CTS frame and a DL MU-MIMOtransmission. The SCH frame is sent with RA=multi-cast in this sequence(shown as being from STA0, which may be an AP).

Each STA receiving SCH frame examines the transmitter address (TA) fieldto see if it matches MAC address of the AP with which the STA isassociated. If TA=AP address for this STA, then the STA examines theSCHED field in the frame to determine if it is an intended recipient ofthe expected subsequent DL MU-MIMO frame and if so, extracts theresponse scheduling information from the SCHED field and uses thisinformation to schedule a subsequent response transmission. Order and/ortiming of response BA transmissions is according to information that wasdelivered within the SCH frame. This embodiment shows STA1 providing itsBA1, followed by STA2 providing its BA2, and so on. However, anyalternative desired order may be employed by which the various STAsprovide their BAs to the transmitting wireless communication device(e.g., STA0 or AP).

In addition, each of the respective STAs may provide its respectiveresponse using a particular cluster (e.g., one or more channels withinone or more bands). For example, while the horizontal axis of thisdiagram properly understood to be that of time, the vertical axis ofthis diagram may be understood to be frequency. As such, each respectiveSTA may provide its respective response using a different respectivecluster. Again, it is noted that a cluster may be viewed as being anycombination of one or more channels within one or more bands. Inalternative embodiments, it is noted that the respective STAs mayprovide their respective responses using a common cluster. That is tosay, each of the respective STAs may provide its respective responseusing the same cluster, yet at different times (e.g., STA1 providing itsresponse using the common cluster during a time 1, the STA2 providingits response using the common cluster during a time 2, and so on).

Of course, it is also noted that various combinations of timing, order,and cluster assignment may also be employed. For example, differentrespective receiving wireless communication devices may provide theirrespective responses using a first cluster, while other respectivewireless communication devices may provide their respective responsesusing a second cluster. That is to say, more than one of the respectivereceiving wireless communication devices may provide their respectiveresponses using a cluster that is different than one or more clustersemployed by other of the receiving wireless communication devices.Moreover, if the transmitting wireless communication device (e.g., STA0)has the capability, functionality, and/or circuitry, etc. to receivesimultaneous communications from more than one receiving wirelesscommunication device, scheduling information may be provided to thereceiving wireless communication devices such that two or more of thereceiving wireless communication devices that provide their respectiveresponses simultaneously (e.g., at the same time/in parallel with oneanother using different respective clusters).

In some embodiments, each respective STA has a specified/predeterminedcluster via which it should provide responses (e.g., such as by adefault configuration, via some assignment provided from the STA0,etc.). In other embodiments, such a signal provided from the STAGprovides cluster assignments by which the respective wirelesscommunication devices are to provide their respective responses to STA0.Such cluster assignment for responses need not be static, but may beadapted and dynamically changed over time. For example, each respectivereceiving wireless communication device may include a sequence ofcluster assignments that there is a function of time, and depending uponthe current time, a given receiving wireless communication device mayoperate in accordance with the current cluster assignment.Alternatively, a transmitting wireless communication device (e.g., STA0)may provide respective cluster assignments at different respective timesto the various receiving wireless communication devices, includingproviding updated or modified cluster assignments at different times.Each respective receiving wireless communication device would thenoperate based upon the most recently received cluster assignment. As maybe understood, a given receiving wireless communication device mayprovide its respective responses using different respective clusters atdifferent respective times (e.g., such as in accordance with differentrespective cluster assignments).

FIG. 19 is a diagram illustrating an embodiment of a timing diagramshowing schedule (SCH) information/frame being transmitted after a clearto send (CTS) frame such that the scheduling information/frame isincluded in a multi-user multiple-input-multiple-output (MU-MIMO) frame(which may include data therein).

This embodiment differs from the previous embodiment at least, in that,scheduling information is actually included within a downlink MU-MIMOframe (e.g., which may include data therein). As may be understood, invarious embodiments, such scheduling information may be provided in aseparate signal than one including data, or within a frame that doesinclude data.

FIG. 20 is a diagram illustrating an embodiment of a timing diagramshowing a schedule (SCH) frame being transmitted after a downlinkmultiple input multiple output (MU-MIMO) frame. In this embodiment, SCHframe sent after DL MU-MIMO transmission. The SCH frame is sent withRA=multi-cast in this sequence. The SCH frame may be sent after thedownlink MU-MIMO frame that follows a request to send/clear to send(RTS/CST) frame exchange.

STA receiving SCH frame examines TA field to see if it matches MACaddress of the AP with which the STA is associated. If TA=AP address forthis STA, then the STA examines the SCHED field in the frame todetermine if it is identified as a responder in this SCH frame, and ifso, it extracts the response scheduling information from the SCHED fieldand uses this information to schedule a subsequent responsetransmission. The order and/or timing of response BA transmissions isaccording to information that was delivered within the SCH frame.

FIG. 21 is a diagram illustrating an embodiment of a timing diagramshowing an exchange employing a modified RTS frame. This embodimentshows schedule information (SCHED field) carried within modified RTSframe. The RTS frame in this exchange has RA=uni-cast. The STA receivingRTS frame examines TA field to see if it matches MAC address of the APwith which the STA is associated. If TA=AP address for this STA, thenthe STA examines the SCHED field in the frame to determine if it is anintended recipient of the expected subsequent DL MU-MIMO frame and ifso, extracts the response scheduling information from the SCHED fieldand schedules a response transmission at the corresponding timeindicated in the SCHED field. The order and/or timing of response BAtransmissions is according to information that was delivered within theSchedule information from the modified RTS frame.

Generally speaking, any of a number of different types of frames may bemodified to include certain scheduling information therein. In fact, anysignal or communication from a transmitting wireless communicationdevice to a number of receiving wireless communication devices mayinclude scheduling information therein to direct the manner by whichresponses are to be provided from those receiving wireless communicationdevices to the transmitting wireless communication device. In addition,as has also been described with respect other embodiments and/ordiagrams herein, additional information such as order, timing, clusterassignment, etc. may also be included within such scheduling informationto direct the manner by which such responses are to be provided from thereceiving wireless communication devices to the transmitting wirelesscommunication device.

FIG. 22 is a diagram illustrating an embodiment of a timing diagramshowing an exchange employing a schedule (SCH) frame at start. Thisembodiment shows schedule information (SCHED field) carried within SCHframe. The SCH frame in this exchange has RA=uni-cast. STA receiving SCHframe examines TA field to see if it matches MAC address of the AP withwhich the STA is associated. If TA=AP address for this STA, then the STAexamines the SCHED field in the frame to determine if it is an intendedrecipient of the expected subsequent DL MU-MIMO frame and if so,extracts the response scheduling information from the SCHED field anduses this information to schedule a subsequent response transmission.

CTS is transmitted according to instructions found in SCH frame. The SCHframe is addressed to uni-cast RA. The STA with MAC address that matchesuni-cast RA of SCH frame responds with CTS frame. The order and/ortiming of response BA transmissions is according to information that wasdelivered within the Schedule information from the SCH frame.

FIG. 23 is a diagram illustrating an embodiment of a wirelesscommunication system in which recovery mechanisms may be performedbetween various wireless communication devices therein. Any of variousrecovery mechanisms may be performed when a transmission is sent from atransmitting wireless communication device (e.g., AP) to variousreceiving wireless communication devices (e.g., STAs). When at least oneof the receiving wireless communication devices (e.g., STAs) fails toprovide a response to the transmitting wireless communication device(e.g., AP), various recovery mechanisms may be performed includingtransmitting a recovery frame from the transmitting wirelesscommunication device (e.g., AP) to one, a subset, or all of thereceiving wireless communication devices (e.g., STAs). Various mannersby which such recovery mechanisms may be performed are described herein.

In accordance with the PCF inter-frame space (PIFS) (where PCF is pointcoordinated function) recovery mechanism in accordance with IEEE802.11n, after a valid response to the initial frame of a TXOP, if theDuration/ID field is set for multiple frame transmission and there is asubsequent transmission failure, the corresponding channel accessfunction may recover transmit after the CS mechanism (see 9.2.1 in IEEE802.11n) indicates that the medium is idle at the TxPIFS slot boundary(defined in 9.2.10 in IEEE 802.11n) before the expiration of the TXNAVtimer. At the expiration of the TXNAV timer, if the channel accessfunction has not regained access to the medium, then the EDCAF shallinvoke the backoff procedure that is described in 9.9.1.5 in IEEE802.11n. Transmission failure is defined in 9.9.1.5 in IEEE 802.11n.

Various acknowledgement methods and mechanisms may be performed inaccordance with the principles herein. For example, suchacknowledgements may be made in response to a multi-user transmission.The recipients of the transmission may need to acknowledge their receiptof their portion of the multi-user transmission.

For example, if the mechanism for acknowledgement is Polled, then anexistent recovery mechanism may be employed. Polled mechanism is underthe direction of the multi-user frame transmitter, which maintainscontrol of the medium by polling, and therefore, recovery is accordingto normal transmitter recovery rules. The MU-TXer follows thetransmission with a sequence of polls which solicit responses. Failedresponses can be followed by more polls.

If the mechanism for acknowledgement is Slotted, then an existentrecovery mechanism may be employed. Slotted acknowledgement passescontrol to each responder in turn according to a slot number. When aresponder fails to occupy its assigned slot, the next slot appears andthe next responder occupies that next slot.

If the mechanism for acknowledgement is Scheduled, then various recoverymechanism approaches and means in accordance with the principlespresented herein and their equivalents may be employed. If an intendedrecipient fails to respond, then the communication medium (e.g., air)might appear to be IDLE in the absence of a response and an unrelatedSTA might attempt to take control of the medium during this IDLE time. Arecovery mechanism may attempt to prevent unwanted STAs from takingcontrol by occupying the IDLE time while simultaneously attempting toretrieve the information that initially failed to be transmitted.

A multi-user scheduled response recovery overview is initially providedbelow with respect to each of recovery mechanism associated withtransmitting wireless communication devices and receiving wirelesscommunication devices.

Transmitter Recovery

A MU-TXer employing scheduled response may transmit a packet to recoverthe channel access mechanism in the case of a failure. Such a recoverypacket may be a POLL frame (e.g., the MU-TXer may fall back to polledmethod to retrieve the remaining response frames if an MU-RXer fails totransmit its corresponding response frame).

A multi-poll frame may be used to poll for the rest of the responseframe(s) when any MU-RXer fails to transmit its corresponding responseframe. A multi-poll frame may include an MU scheduling field providingresponse schedule information for the MU-RXer(s) that have nottransmitted their response frames as of the time of the transmission ofthe multi-poll frame.

The MU-TXer may recover if it does not receive a multi-user responsefrom an intended MU-RXer j after some period of time (e.g., R seconds)from the originally scheduled response transmission time. Recipientsmust cancel any pre-scheduled response transmissions if a POLL orMULTI-POLL frame is transmitted. This time period, R, may be PIFS.

The MU-TXer may recover if the medium is not IDLE when the responseframe is expected, and a response frame is not received successfully atexpected time.

Receiver Recovery

Such operation may be performed if a receiver j (e.g., MU-RXer j) doesnot receive a packet successfully, but that receiver j knows that it isan intended receiver of at least a portion of a multi-user packet.

The MU-RXer j may transmit, at the scheduled response time, a packetindicating it has failed to receive/decode a multi-user packetsuccessfully. The transmission must not take longer than the time thatwas originally scheduled for the response transmission. Informationindicating that the receiver j is an intended receiver may be obtainedby examining the contents of any one or more of: Group ID if it is notoverloaded, MAC address included in MAC header, Modified MPDU delimiter,Modified RTS.

Considering even more details related to transmitter recovery,transmitter recovery mechanisms may be performed after a two-way frameexchange preceding the exchange of frames between a MU-TXer and one ormore MU-RXers. Frames in the two-way exchange contain DUR informationwhich is received by other STAs. These frames have uni-cast RA and aregenerally transmitted at lower rates in order to maximize theprobability of reception by third-party receivers. The MU-TXer can trackthe transmitted DUR information with a TXNAV counter.

If a MU-TXer does not receive an expected response/feedback from anintended MU-RXer and the MU-TXer is tracking the DUR information with aTXNAV counter and the TXNAV is non-zero, a variety of operations may beperformed.

For example, not receiving an expected response means that the medium isdetermined by the MU-TXer to be IDLE for PIFS time from the start of thetime scheduled for the beginning of the transmission of the expectedresponse.

If the mechanism for acknowledgement is Polled or Slotted, then existingoperations may be performed.

If the mechanism for acknowledgement is Scheduled, then the MU-TXer cantransmit a recovery frame after some period of time (e.g., R seconds).Various examples of such recovery frames include any one or combinationof a control, a management frame, and data frame. The recovery frame canbe a poll frame transmitted to the station that failed to transmit themulti-user response. The MU-RXer that failed to respond can be polledfor the response/feedback frame that corresponds to the previouslytransmitted multi-user transmission. The MU-RXer that failed to respondcan be polled for a response/feedback frame that does not correspond tothe previously transmitted multi-user transmission.

The recovery frame can be a poll to another station made for requestinga feedback/response frame. The recovery frame can be to a differentstation after X seconds of polling one station and failing to receive anexpected response.

Such recovery mechanisms may be performed for a MU-RXer that iscurrently scheduled to transmit a response, that has not yet transmittedthat response, and/or that receives a new transmission from the MU-TXer.Such a MU-RXer shall cancel its scheduled response transmission (e.g.,note the imperative nature of such cancellation).

Such recovery mechanisms may be performed for a MU-TXer should (e.g.,note the permissive/allowable nature of such cancellation) use a datatransmission rate for recovery transmissions that is likely to bereceivable by all of the MU-RXers corresponding to the MU transmissionfor which recovery is being performed. This may be performed to ensurethat all MU-RXers that are awaiting their scheduled response time willhear a recovery transmission and then cancel their scheduled responsetransmissions.

If the expected multi-user response is an ACK/BA and a MU-TXer jdetermines that the medium has been IDLE for PIFS following thescheduled time for the ACK/BA transmission, then a number of variousoperations may be performed by a transmitter. For example, thetransmitter may poll MU-RXer j for ACK/BA. Alternatively, thetransmitter may poll MU-RXer j for information about previously receivedpackets (e.g., sequence number or fragment number) within a window ofsize of Y or previously transmitted packets to MU-RXer j. If desired,the transmitter may poll MU-RXer< >j for ACK/BA.

In certain instances, a multi-poll frame may be used to poll MU-RXer jand the rest of MU-RXer's that has not transmitted their ACK/BA fortheir response frame. In other situations, a multi-poll frame may beused to poll the rest of MU-RXer's (e.g., MU-RXer≠j) that has nottransmitted their ACK/BA for their response frame.

If the expected multi-user response is channel feedback and an MU-TXer jdetermines that the medium has been IDLE for some period of time (e.g.,PIFS) following the scheduled time for the transmission of the channelfeedback. The transmitter may poll MU-RXer j for channel feedback. TheMU-RXr j may respond with old channel information, new channelinformation, no channel information and/or an indication that newsounding is needed.

The transmitter may poll MU-RXer j to inquire about the quality of thereceived signal (e.g., to solicit performance measurement informationsuch as SINR or effective SNR). The MU-TXer may use the information todecide if sending another sounding sequence is required.

A multi-poll frame may be used to poll MU-RXer j and the rest of MU-RXerthat has not transmitted their channel feedback or other channel relatedinformation. The MU-RXer J may be polled for quality of received signaland the rest of stations may be polled for their channel feedback.

A multi-poll frame may be used to poll the rest of MU-RXer ((i.e.MU-RXer≠j)) that has not transmitted their channel feedback.

Transmitter recovery scheme may be used when a BA or feedback frame istransmitted and the MU-TXer detects energy or a packet that does notdecode to the expected response frame, or results in a frame receptionwith errors. For example, such an instance may arise when the MU-TXermay fail to receive the BA or response frame that is transmitted due tovarious reasons including low SNR, collision with other transmittedframe, etc. Such an instance may alternatively arise when the respondermay transmit the BA or response frame at the scheduled time, but the CRCindicates an error. Such a failure situation may arise if the respondertransmits the BA or response frame at the scheduled time, but some PHYprocessing in the receiver may fail to recover the packet.

The two methods below may be used to recover BA/ACK or feedback frames.

First method: the MU-TXer may transmit a recovery message after thescheduled time for any subset of the participating stations to ask forBA(s)/ACK(s), feedback frame, or other response frames from stations(e.g., if a BA/ACK or feedback frame was not received successfully. ASCH frame may be used to request/schedule a response frame for stationswhose responses were not received successfully.

Second method: MU-TXer can set schedule times for each responding STAsuch that the time between successive responding STA transmissions isgreater than the time that would be needed for just the ACK or BAtransmission (e.g., the time could accommodate the BA transmission plusan additional PIFS or 2×PIFS). An extended interval would allow forrecovery due to FCS failure of a transmitted BA. For example, byincluding an additional 1×PIFS or 2×PIFS before the next responder isscheduled to start transmitting, the MU-TXer can initiate Transmitterrecovery as previously described herein (e.g., by generating andtransmitting a poll frame specifying such an additional time duration).

Considering even more details related to receiver recovery, receiverrecovery may be performed when a MU-RXer might fail to receive a packetsuccessfully (e.g. FCS failure occurs, some other type of failure,etc.), but the receiver might know that it is an intended receiver ofthe failed reception using one of the various mechanisms provided below.

The group ID in the signal field may be an indication to a STA that itis an intended receiver for a packet. If group ID over loading is used,group ID may not be enough for a receiver to know definitively that itis an intended receiver of a packet, so additional or other mechanismsmay be employed.

AMPDU MPDU Delimiter with AID for MU may be used for the receiver STA todetermine if it is an intended receiver. If this method is used and theCRC within the delimiter is valid, then the station has a mechanism toestablish it is the intended receiver.

MAC header may correctly indicate with high probability which station isthe source even if the FCS fails. CRC may be added to the MAC header tocheck if MAC header is received correctly.

A modified RTS may be used for a receive station to establish whether ornot it is an intended receiver for a multi-user packet.

A SCH frame used to carry scheduled information may be used to provideinformation about the intended receivers. It is noted that, if the SCHframe is correctly received, then this information is definitive.

Portions of the DL MU-MIMO packet may not be received successfully butthe scheduled time for the receiver performing the recovery may havebeen correctly determined from a SCH frame reception preceding the DLMU-MIMO transmission, a SCHED field included in an MPDU within the DLMU-MIMO transmission, and/or a Modified RTS that carries the scheduleinformation in an SCHED field.

If a frame that is not received successfully is a data packet for whichthe receiver would have transmitted an ACK/BA had the reception beensuccessful, then the receiver may transmit a frame that provides thetransmitter with information indicating that it has not received anydata frame successfully. For example, a BA frame may carry informationsuch as the sequence numbers and/or fragment numbers of validly receivedMPDU/MSDUs from the transmitter of the multi-user packet. Alternatively,a NACK frame may carry information indicating that no data was receivedcorrectly. A BA frame with no ACK bits set to “1” is one form of a NACKframe. The transmitted frame should have the same length as theoriginally expected ACK or BA frame. Alternatively, the transmittedframe may be shorter than the originally expected frame.

Instead, if a frame that is not received successfully is a managementrequest or control frame for which the MU-RXer would have transmitted aresponse. If the MU-RXer can establish that it was the intendedrecipient, and it can determine which STA was the MU-TXer, then it cantransmit a response recovery frame. The transmitted response recoveryframe should have the same length as the originally expected responseframe had the management or control frame been received successfully.

A MU-RXer might fail to receive a channel sounding frame properly but itmight know that it is a receiver that is scheduled to send feedback inresponse to the failed reception. For example, an NDP announcement framethat preceded the sounding frame may have contained information for theMU-RXer indicating that it is a sounded station and indicating what timeor order it is expected to send feedback. Alternatively, an NDP framemay contain information as to which MU-RXers are sounded and in whattime or order they are expected to send feedback. A modified RTS or aSCH frame carrying scheduled information may be used to indicate whichSTAs have been sounded and may contain their scheduled response time.

A sounded MU-RXer which failed to receive an NDP sounding sequencesuccessfully but has definitive knowledge indicating that it has ascheduled response time may transmit a feedback recovery packet with thesame length as the expected channel feedback frame that it would havetransmitted if it had received the NDP sequence successfully. Thefeedback recovery packet may contain feedback information that is basedon the last received sounding frame and/or subsequent frame exchanges.The feedback recovery packet may include the following information inits recovery response/feedback such as via an indication that it hasfailed to receive the NDP sequence successfully or via an indicationthat resounding is needed, if channel resounding is needed.

FIG. 24A, FIG. 24B, FIG. 25A, FIG. 25B, FIG. 26A, FIG. 26B, FIG. 27A,and FIG. 27B are diagrams illustrating embodiments of methods foroperating one or more wireless communication devices.

The methods of FIG. 24A, FIG. 24B, FIG. 25A, FIG. 25B, and FIG. 26A maygenerally be viewed as being performed within a transmitting wirelesscommunication device (e.g., an AP or a STA). The methods of FIG. 26B,FIG. 27A, and FIG. 27B may generally be viewed as being performed withina receiving wireless communication device (e.g., such as a STA).

Referring to method 2400 of FIG. 24A, the method 2400 begins bytransmitting a signal, that includes scheduling information, to wirelesscommunication devices, as shown in a block 2410. The method 2400continues by failing to receive expected response (e.g., ACK/BA) from atleast one of the wireless communication devices (e.g., MU-RXer j) for Δt(e.g., PIFS) following scheduled time for responses from wirelesscommunication devices, as shown in a block 2420. Based upon thisfailure, the method 2400 then operates by transmitting poll frame tosingle wireless communication device, as shown in a block 2430. Incertain embodiments, the poll frame may undergo transmission to MU-RXerj for ACK/BA, as shown in a block 2430 a. In other embodiments, the pollframe may undergo transmission to MU-RXer j for information related toor regarding previously received packets, as shown in a block 2430 b. Ineven other embodiments, the operations may involve polling MU-RXer k(k≠j) for ACK/BA, as shown in a block 2430 c.

Referring to method 2401 of FIG. 24B, the method 2401 begins bytransmitting a signal, that includes scheduling information, to wirelesscommunication devices, as shown in a block 2411. The method 2401 thenoperates by failing to receive expected response (e.g., ACK/BA) from atleast one of the wireless communication devices (e.g., MU-RXer j) for Δt(e.g., PIFS) following scheduled time for responses from wirelesscommunication devices, as shown in a block 2421.

The method 2401 continues by transmitting multi-poll frame to multiplewireless communication devices, as shown in a block 2431. In someembodiments, the multi-poll frame may be transmitted to MU-RXer j andany MU-RXer from which a respective ACK/BA has not been received, asshown in a block 2431 a. In even other embodiments, the multi-poll framemay be transmitted to any MU-RXer from which a respective ACK/BA has notbeen received, as shown in a block 2431 b.

Referring to method 2500 of FIG. 25A, the method 2500 begins bytransmitting a signal, that includes scheduling information, to wirelesscommunication devices, as shown in a block 2510. The method 2500continues by failing to receive expected response (e.g., channelfeedback) from at least one of the wireless communication devices (e.g.,MU-RXer j) for Δt (e.g., PIFS) following scheduled time for responsesfrom wireless communication devices, as shown in a block 2520.

The method 2500 then operates by transmitting poll frame to singlewireless communication device, as shown in a block 2530. In someembodiments, the poll frame may undergo transmission to MU-RXer j forchannel feedback, as shown in a block 2530 a. In other embodiments, thepoll frame may undergo transmission to MU-RXer j thereby making aninquiry related to the quality of a received signal, as shown in a block2530 b.

Referring to method 2501 of FIG. 25B, the method 2501 begins bytransmitting a signal, that includes scheduling information, to wirelesscommunication devices, as shown in a block 2511. The method 2501 thenoperates by failing to receive expected response (e.g., channelfeedback) from at least one of the wireless communication devices (e.g.,MU-RXer j) for Δt (e.g., PIFS) following scheduled time for responsesfrom wireless communication devices, as shown in a block 2521.

The method 2501 continues by transmitting a multi-poll frame to multiplewireless communication devices, as shown in a block 2531. In someembodiments, the multi-poll frame may undergo transmission to MU-RXer jand any MU-RXer from which respective channel feedback has not beenreceived, as shown in a block 2531 a. In other embodiments, themulti-poll frame may undergo transmission to any MU-RXer from whichrespective channel feedback has not been received, as shown in a block2531 b. In even other embodiments, the multi-poll frame may undergotransmission to an MU-RXer j thereby making an inquiry related to thequality of received signal and any MU-RXer from which respective channelfeedback has not been received for their channel feedback, as shown in ablock 2531 c.

Referring to method 2600 of FIG. 26A, the method 2600 begins bytransmitting a signal, that includes scheduling information, to wirelesscommunication devices, as shown in a block 2610. The method 2600continues by detecting energy or packet (e.g., ACK/BA, feedback framefrom one of the wireless communication devices, e.g., MU-RXer j) thatdoes not decode to expected frame (e.g., collisions, low SNR, CRC fails,errors, PHY processing failure, etc.), as shown in a block 2620.

The method 2600 then operates by performing recovery scheme, as shown ina block 2630. Any of a variety of recovery schemes may be employed inaccordance with the various aspects presented herein or theirequivalents.

Referring to method 2601 of FIG. 26B, in accordance with determiningthat the receiving wireless communication device is an intended MU-RXer,the method 2601 begins by failing to receive data packet successfully(e.g., FCS failure, partial decoding error, etc.), as shown in a block2611. The method 2601 then operates by transmitting frame (e.g., to AP),with same [or shorter] length as expected response), indicatingunsuccessful reception, as shown in a block 2621.

Referring to method 2700 of FIG. 27A, in accordance with determiningthat the receiving wireless communication device is an intended MU-RXer,the method 2700 begins by failing to receive management framesuccessfully, as shown in a block 2710. The method 2700 continues bytransmitting response recovery frame (e.g., to AP) with same length asexpected response, as shown in a block 2720.

Referring to method 2701 of FIG. 27B, in accordance with determiningthat the receiving wireless communication device is an intended MU-RXer,the method 2701 begins by failing to receive sounding framesuccessfully, as shown in a block 2711. The method 2701 then operates bytransmitting feedback recovery frame (e.g., to AP) with same length asexpected channel feedback frame (e.g., same length in NDP sequencereceived successfully), as shown in a block 2721.

In some embodiments, feedback recovery frame may be implemented asincluding feedback information based on last received sounding frameand/or subsequent frame exchanges, as shown in a block 2721 a. In otherembodiments, the feedback recovery frame may be implemented as includingindication of failure to receive NPD sequence successfully, as shown ina block 2721 b. In even other embodiments, the feedback recovery framemay be implemented as including indication that re-sounding needed, asshown in a block 2721 c.

It is also noted that the various operations and functions as describedwith respect to various methods herein may be performed within awireless communication device, such as using a baseband processingmodule and/or a processing module implemented therein, (e.g., such as inaccordance with the baseband processing module 64 and/or the processingmodule 50 as described with reference to FIG. 2) and/or other componentstherein. For example, such a baseband processing module can generatesuch signals and frames as described herein as well as perform variousoperations and analyses as described herein, or any other operations andfunctions as described herein, etc. or their respective equivalents.

In some embodiments, such a baseband processing module and/or aprocessing module (which may be implemented in the same device orseparate devices) can perform such processing to generate signals fortransmission using at least one of any number of radios and at least oneof any number of antennae to another wireless communication device(e.g., which also may include at least one of any number of radios andat least one of any number of antennae) in accordance with variousaspects of the invention, and/or any other operations and functions asdescribed herein, etc. or their respective equivalents. In someembodiments, such processing is performed cooperatively by a processingmodule in a first device, and a baseband processing module within asecond device. In other embodiments, such processing is performed whollyby a baseband processing module or a processing module.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “operably coupled to”, “coupled to”, and/or “coupling” includesdirect coupling between items and/or indirect coupling between items viaan intervening item (e.g., an item includes, but is not limited to, acomponent, an element, a circuit, and/or a module) where, for indirectcoupling, the intervening item does not modify the information of asignal but may adjust its current level, voltage level, and/or powerlevel. As may further be used herein, inferred coupling (i.e., where oneelement is coupled to another element by inference) includes direct andindirect coupling between two items in the same manner as “coupled to”.As may even further be used herein, the term “operable to” or “operablycoupled to” indicates that an item includes one or more of powerconnections, input(s), output(s), etc., to perform, when activated, oneor more its corresponding functions and may further include inferredcoupling to one or more other items. As may still further be usedherein, the term “associated with”, includes direct and/or indirectcoupling of separate items and/or one item being embedded within anotheritem. As may be used herein, the term “compares favorably”, indicatesthat a comparison between two or more items, signals, etc., provides adesired relationship. For example, when the desired relationship is thatsignal 1 has a greater magnitude than signal 2, a favorable comparisonmay be achieved when the magnitude of signal 1 is greater than that ofsignal 2 or when the magnitude of signal 2 is less than that of signal1.

As may also be used herein, the terms “processing module”, “module”,“processing circuit”, and/or “processing unit” (e.g., including variousmodules and/or circuitries such as may be operative, implemented, and/orfor encoding, for decoding, for baseband processing, etc.) may be asingle processing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module,module, processing circuit, and/or processing unit may have anassociated memory and/or an integrated memory element, which may be asingle memory device, a plurality of memory devices, and/or embeddedcircuitry of the processing module, module, processing circuit, and/orprocessing unit. Such a memory device may be a read-only memory (ROM),random access memory (RAM), volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module,module, processing circuit, and/or processing unit includes more thanone processing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,and/or processing unit implements one or more of its functions via astate machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory and/or memory element storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. Still further note that, the memoryelement may store, and the processing module, module, processingcircuit, and/or processing unit executes, hard coded and/or operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated in one or more of the Figures. Such a memorydevice or memory element can be included in an article of manufacture.

The present invention has been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention. Further, theboundaries of these functional building blocks have been arbitrarilydefined for convenience of description. Alternate boundaries could bedefined as long as the certain significant functions are appropriatelyperformed. Similarly, flow diagram blocks may also have been arbitrarilydefined herein to illustrate certain significant functionality. To theextent used, the flow diagram block boundaries and sequence could havebeen defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claimed invention. One of average skill in the artwill also recognize that the functional building blocks, and otherillustrative blocks, modules and components herein, can be implementedas illustrated or by discrete components, application specificintegrated circuits, processors executing appropriate software and thelike or any combination thereof. The present invention may have alsobeen described, at least in part, in terms of one or more embodiments.An embodiment of the present invention is used herein to illustrate thepresent invention, an aspect thereof, a feature thereof, a conceptthereof, and/or an example thereof. A physical embodiment of anapparatus, an article of manufacture, a machine, and/or of a processthat embodies the present invention may include one or more of theaspects, features, concepts, examples, etc. described with reference toone or more of the embodiments discussed herein. Further, from figure tofigure, the embodiments may incorporate the same or similarly namedfunctions, steps, modules, etc. that may use the same or differentreference numbers and, as such, the functions, steps, modules, etc. maybe the same or similar functions, steps, modules, etc. or differentones.

Unless specifically stated to the contra, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of the various embodimentsof the present invention. A module includes a functional block that isimplemented via hardware to perform one or module functions such as theprocessing of one or more input signals to produce one or more outputsignals. The hardware that implements the module may itself operate inconjunction software, and/or firmware. As used herein, a module maycontain one or more sub-modules that themselves are modules.

While particular combinations of various functions and features of thepresent invention have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent invention is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

Mode Selection Tables:

TABLE 1 2.4 GHz, 20/22 MHz channel BW, 54 Mbps max bit rate Code RateModulation Rate NBPSC NCBPS NDBPS EVM Sensitivity ACR AACR 1 Barker BPSK2 Barker QPSK 5.5 CCK 6 BPSK 0.5 1 48 24 −5 −82 16 32 9 BPSK 0.75 1 4836 −8 −81 15 31 11 CCK 12 QPSK 0.5 2 96 48 −10 −79 13 29 18 QPSK 0.75 296 72 −13 −77 11 27 24 16-QAM 0.5 4 192 96 −16 −74 8 24 36 16-QAM 0.75 4192 144 −19 −70 4 20 48 64-QAM 0.666 6 288 192 −22 −66 0 16 54 64-QAM0.75 6 288 216 −25 −65 −1 15

TABLE 2 Channelization for Table 1 Channel Frequency (MHz) 1 2412 2 24173 2422 4 2427 5 2432 6 2437 7 2442 8 2447 9 2452 10 2457 11 2462 12 2467

TABLE 3 Power Spectral Density (PSD) Mask for Table 1 PSD Mask 1Frequency Offset dBr −9 MHz to 9 MHz 0 +/−11 MHz −20 +/−20 MHz −28 +/−30MHz and greater −50

TABLE 4 5 GHz, 20 MHz channel BW, 54 Mbps max bit rate Code RateModulation Rate NBPSC NCBPS NDBPS EVM Sensitivity ACR AACR 6 BPSK 0.5 148 24 −5 −82 16 32 9 BPSK 0.75 1 48 36 −8 −81 15 31 12 QPSK 0.5 2 96 48−10 −79 13 29 18 QPSK 0.75 2 96 72 −13 −77 11 27 24 16-QAM 0.5 4 192 96−16 −74 8 24 36 16-QAM 0.75 4 192 144 −19 −70 4 20 48 64-QAM 0.666 6 288192 −22 −66 0 16 54 64-QAM 0.75 6 288 216 −25 −65 −1 15

TABLE 5 Channelization for Table 4 Frequency Frequency Channel (MHz)Country Channel (MHz) Country 240 4920 Japan 244 4940 Japan 248 4960Japan 252 4980 Japan 8 5040 Japan 12 5060 Japan 16 5080 Japan 36 5180USA/Europe 34 5170 Japan 40 5200 USA/Europe 38 5190 Japan 44 5220USA/Europe 42 5210 Japan 48 5240 USA/Europe 46 5230 Japan 52 5260USA/Europe 56 5280 USA/Europe 60 5300 USA/Europe 64 5320 USA/Europe 1005500 USA/Europe 104 5520 USA/Europe 108 5540 USA/Europe 112 5560USA/Europe 116 5580 USA/Europe 120 5600 USA/Europe 124 5620 USA/Europe128 5640 USA/Europe 132 5660 USA/Europe 136 5680 USA/Europe 140 5700USA/Europe 149 5745 USA 153 5765 USA 157 5785 USA 161 5805 USA 165 5825USA

TABLE 6 2.4 GHz, 20 MHz channel BW, 192 Mbps max bit rate ST TX CodeCode Rate Antennas Rate Modulation Rate NBPSC NCBPS NDBPS  12 2 1 BPSK0.5  1  48  24  24 2 1 QPSK 0.5  2  96  48  48 2 1 16-QAM 0.5  4 192  96 96 2 1 64-QAM 0.666 6 288 192 108 2 1 64-QAM 0.75  6 288 216  18 3 1BPSK 0.5  1  48  24  36 3 1 QPSK 0.5  2  96  48  72 3 1 16-QAM 0.5  4192  96 144 3 1 64-QAM 0.666 6 288 192 162 3 1 64-QAM 0.75  6 288 216 24 4 1 BPSK 0.5  1  48  24  48 4 1 QPSK 0.5  2  96  48  96 4 1 16-QAM0.5  4 192  96 192 4 1 64-QAM 0.666 6 288 192 216 4 1 64-QAM 0.75  6 288216

TABLE 7 Channelization for Table 6 Channel Frequency (MHz) 1 2412 2 24173 2422 4 2427 5 2432 6 2437 7 2442 8 2447 9 2452 10 2457 11 2462 12 2467

TABLE 8 5 GHz, 20 MHz channel BW, 192 Mbps max bit rate ST TX Code CodeRate Antennas Rate Modulation Rate NBPSC NCBPS NDBPS  12 2 1 BPSK 0.5  1 48  24  24 2 1 QPSK 0.5  2  96  48  48 2 1 16-QAM 0.5  4 192  96  96 21 64-QAM 0.666 6 288 192 108 2 1 64-QAM 0.75  6 288 216  18 3 1 BPSK0.5  1  48  24  36 3 1 QPSK 0.5  2  96  48  72 3 1 16-QAM 0.5  4 192  96144 3 1 64-QAM 0.666 6 288 192 162 3 1 64-QAM 0.75  6 288 216  24 4 1BPSK 0.5  1  48  24  48 4 1 QPSK 0.5  2  96  48  96 4 1 16-QAM 0.5  4192  96 192 4 1 64-QAM 0.666 6 288 192 216 4 1 64-QAM 0.75  6 288 216

TABLE 9 channelization for Table 8 Frequency Frequency Channel (MHz)Country Channel (MHz) Country 240 4920 Japan 244 4940 Japan 248 4960Japan 252 4980 Japan 8 5040 Japan 12 5060 Japan 16 5080 Japan 36 5180USA/Europe 34 5170 Japan 40 5200 USA/Europe 38 5190 Japan 44 5220USA/Europe 42 5210 Japan 48 5240 USA/Europe 46 5230 Japan 52 5260USA/Europe 56 5280 USA/Europe 60 5300 USA/Europe 64 5320 USA/Europe 1005500 USA/Europe 104 5520 USA/Europe 108 5540 USA/Europe 112 5560USA/Europe 116 5580 USA/Europe 120 5600 USA/Europe 124 5620 USA/Europe128 5640 USA/Europe 132 5660 USA/Europe 136 5680 USA/Europe 140 5700USA/Europe 149 5745 USA 153 5765 USA 157 5785 USA 161 5805 USA 165 5825USA

TABLE 10 5 GHz, with 40 MHz channels and max bit rate of 486 Mbps TX STCode Code Rate Antennas Rate Modulation Rate NBPSC 13.5 Mbps  1 1 BPSK0.5 1  27 Mbps 1 1 QPSK 0.5 2  54 Mbps 1 1 16-QAM 0.5 4 108 Mbps 1 164-QAM 0.666 6 121.5 Mbps  1 1 64-QAM 0.75 6  27 Mbps 2 1 BPSK 0.5 1  54Mbps 2 1 QPSK 0.5 2 108 Mbps 2 1 16-QAM 0.5 4 216 Mbps 2 1 64-QAM 0.6666 243 Mbps 2 1 64-QAM 0.75 6 40.5 Mbps  3 1 BPSK 0.5 1  81 Mbps 3 1 QPSK0.5 2 162 Mbps 3 1 16-QAM 0.5 4 324 Mbps 3 1 64-QAM 0.666 6 365.5 Mbps 3 1 64-QAM 0.75 6  54 Mbps 4 1 BPSK 0.5 1 108 Mbps 4 1 QPSK 0.5 2 216Mbps 4 1 16-QAM 0.5 4 432 Mbps 4 1 64-QAM 0.666 6 486 Mbps 4 1 64-QAM0.75 6

TABLE 11 Power Spectral Density (PSD) mask for Table 10 PSD Mask 2Frequency Offset dBr −19 MHz to 19 MHz 0 +/−21 MHz −20 +/−30 MHz −28+/−40 MHz and greater −50

TABLE 12 Channelization for Table 10 Frequency Frequency Channel (MHz)Country Channel (MHz) County 242 4930 Japan 250 4970 Japan 12 5060 Japan38 5190 USA/Europe 36 5180 Japan 46 5230 USA/Europe 44 5520 Japan 545270 USA/Europe 62 5310 USA/Europe 102 5510 USA/Europe 110 5550USA/Europe 118 5590 USA/Europe 126 5630 USA/Europe 134 5670 USA/Europe151 5755 USA 159 5795 USA

What is claimed is:
 1. A wireless communication device comprising: aprocessor configured to: transmit, via a plurality of sub-carriers, afirst frame to a first other wireless communication device and a secondother wireless communication device; and receive a second frame from thefirst other wireless communication device and the second other wirelesscommunication device, wherein the second frame includes first data fromthe first other wireless communication device within a first subset ofsub-carriers of the plurality of sub-carriers and includes second datafrom the second other wireless communication device within a secondsubset of sub-carriers of the plurality of sub-carriers that isdifferent than the first subset of sub-carriers of the plurality ofsub-carriers.
 2. The wireless communication device of claim 1, whereinthe processor is further configured to: generate the first frame toinclude scheduling information that specifies a time during which thefirst other wireless communication device is to transmit the first datato the wireless communication device via the first subset ofsub-carriers of the plurality of sub-carriers and also during which thesecond other wireless communication device is to transmit the seconddata to the wireless communication device via the second subset ofsub-carriers of the plurality of sub-carriers.
 3. The wirelesscommunication device of claim 1, wherein the processor is furtherconfigured to: generate the first frame to include schedulinginformation, wherein the scheduling information specifies a first timeduring which the first other wireless communication device is permittedto transmit the first data to the wireless communication device via thefirst subset of sub-carriers of the plurality of sub-carriers and alsoduring which the second other wireless communication device is totransmit the second data to the wireless communication device via thesecond subset of sub-carriers of the plurality of sub-carriers, andwherein the scheduling information also specifies a second time duringwhich a third other wireless communication device is permitted totransmit third data to the wireless communication device via at leastone subset of sub-carriers of the plurality of sub-carriers; receive thesecond frame from the first other wireless communication device and thesecond other wireless communication device via an orthogonal frequencydivision multiple access (OFDMA) transmission; and receive, via the atleast one subset of sub-carriers of the plurality of sub-carriers, athird frame that includes the third data from the third other wirelesscommunication device.
 4. The wireless communication device of claim 1,wherein the processor is further configured to: transmit the first framebased on multi-user multiple-input-multiple-output (MU-MIMO) signaling;and receive the second frame based on orthogonal frequency divisionmultiple access (OFDMA) signaling.
 5. The wireless communication deviceof claim 1, wherein the processor is further configured to: generate thefirst frame to include cluster assignment for the plurality ofsub-carriers, wherein the cluster assignment specifies a plurality ofclusters, wherein a first cluster of the plurality of clusters includesa first at least one channel that is included within a first at leastone band, and a second cluster of the plurality of clusters includes asecond at least one channel that is included within a second at leastone band; and receive a third frame from the first other wirelesscommunication device and the second other wireless communication device,wherein the third frame includes third data from the first otherwireless communication device within the first cluster and fourth datafrom the second other wireless communication device within the secondcluster.
 6. The wireless communication device of claim 1, wherein theprocessor is further configured to: generate the first frame to includecluster assignment for the plurality of sub-carriers, wherein thecluster assignment specifies a plurality of clusters, wherein a firstcluster of the plurality of clusters includes a first at least onechannel that is included within a first at least one band, and a secondcluster of the plurality of clusters includes a second at least onechannel that is included within a second at least one band; and receive,in response to the first frame, a first response from the first otherwireless communication device within the first cluster and a secondresponse from the second other wireless communication device within thesecond cluster.
 7. The wireless communication device of claim 6, whereinat least one of the first response or the second response includes anacknowledgement (ACK), a block acknowledgement (BA), or a trainingfeedback frame.
 8. The wireless communication device of claim 1 furthercomprising: an access point (AP), wherein at least one of the firstother wireless communication device or the second other wirelesscommunication device includes a wireless station (STA).
 9. A wirelesscommunication device comprising: a processor configured to: transmit,via a plurality of sub-carriers and frame based on multi-usermultiple-input-multiple-output (MU-MIMO) signaling, a first frame to aplurality of other wireless communication devices, wherein the firstframe includes a plurality of scheduled response times during which theplurality of other wireless communication devices are to transmit to thewireless communication device; receive, during a first scheduledresponse time of the plurality of schedules response times, a secondframe based on orthogonal frequency division multiple access (OFDMA)signaling that includes first data from a first other wirelesscommunication device of the plurality of other wireless communicationdevices within a first subset of sub-carriers of the plurality ofsub-carriers and includes second data from a second other wirelesscommunication device of the plurality of other wireless communicationdevices within a second subset of sub-carriers of the plurality ofsub-carriers that is different than the first subset of sub-carriers ofthe plurality of sub-carriers; and receive, during a second scheduledresponse time of the plurality of schedules response times, at least oneother frame that includes at least one other data from at least oneother wireless communication device of the plurality of other wirelesscommunication devices.
 10. The wireless communication device of claim 9,wherein the processor is further configured to: receive, during a thirdscheduled response time of the plurality of schedules response times, athird frame based on the OFDMA signaling that includes third data fromthe first other wireless communication device of the plurality of otherwireless communication devices within the first subset of sub-carriersof the plurality of sub-carriers and includes fourth data from a thirdother wireless communication device of the plurality of other wirelesscommunication devices within the second subset of sub-carriers of theplurality of sub-carriers.
 11. The wireless communication device ofclaim 9, wherein: the first data includes at least one of a firstacknowledgement (ACK), a first block acknowledgement (BA), or a firsttraining feedback frame; and the second data includes at least one of asecond ACK, a second BA, or a second training feedback frame.
 12. Thewireless communication device of claim 9 further comprising: a firstwireless station (STA), wherein the first other wireless communicationdevice includes a second STA, and the second other wirelesscommunication device includes a third STA.
 13. The wirelesscommunication device of claim 9 further comprising: an access point(AP), wherein at least one of the first other wireless communicationdevice or the second other wireless communication device includes awireless station (STA).
 14. A method for execution by a wirelesscommunication device, the method comprising: transmitting, via acommunication interface of the wireless communication device and via aplurality of sub-carriers, a first frame to a first other wirelesscommunication device and a second other wireless communication device;and receiving, via the communication interface of the wirelesscommunication device, a second frame from the first other wirelesscommunication device and the second other wireless communication device,wherein the second frame includes first data from the first otherwireless communication device within a first subset of sub-carriers ofthe plurality of sub-carriers and includes second data from the secondother wireless communication device within a second subset ofsub-carriers of the plurality of sub-carriers that is different than thefirst subset of sub-carriers of the plurality of sub-carriers.
 15. Themethod of claim 14 further comprising: generating the first frame toinclude scheduling information that specifies a time during which thefirst other wireless communication device is to transmit the first datato the wireless communication device via the first subset ofsub-carriers of the plurality of sub-carriers and also during which thesecond other wireless communication device is to transmit the seconddata to the wireless communication device via the second subset ofsub-carriers of the plurality of sub-carriers.
 16. The method of claim14 further comprising: generating the first frame to include schedulinginformation, wherein the scheduling information specifies a first timeduring which the first other wireless communication device is permittedto transmit the first data to the wireless communication device via thefirst subset of sub-carriers of the plurality of sub-carriers and alsoduring which the second other wireless communication device is totransmit the second data to the wireless communication device via thesecond subset of sub-carriers of the plurality of sub-carriers, andwherein the scheduling information also specifies a second time duringwhich a third other wireless communication device is permitted totransmit third data to the wireless communication device via at leastone subset of sub-carriers of the plurality of sub-carriers; receivingthe second frame from the first other wireless communication device andthe second other wireless communication device via an orthogonalfrequency division multiple access (OFDMA) transmission; and receiving,via the at least one subset of sub-carriers of the plurality ofsub-carriers, a third frame that includes the third data from the thirdother wireless communication device.
 17. The method of claim 14 furthercomprising: transmitting the first frame based on multi-usermultiple-input-multiple-output (MU-MIMO) signaling; and receiving thesecond frame based on orthogonal frequency division multiple access(OFDMA) signaling.
 18. The method of claim 14 further comprising:generating the first frame to include cluster assignment for theplurality of sub-carriers, wherein the cluster assignment specifies aplurality of clusters, wherein a first cluster of the plurality ofclusters includes a first at least one channel that is included within afirst at least one band, and a second cluster of the plurality ofclusters includes a second at least one channel that is included withina second at least one band; and receiving a third frame from the firstother wireless communication device and the second other wirelesscommunication device, wherein the third frame includes third data fromthe first other wireless communication device within the first clusterand fourth data from the second other wireless communication devicewithin the second cluster.
 19. The method of claim 14 furthercomprising: generating the first frame to include cluster assignment forthe plurality of sub-carriers, wherein the cluster assignment specifiesa plurality of clusters, wherein a first cluster of the plurality ofclusters includes a first at least one channel that is included within afirst at least one band, and a second cluster of the plurality ofclusters includes a second at least one channel that is included withina second at least one band; and receiving, in response to the firstframe, a first response from the first other wireless communicationdevice within the first cluster and a second response from the secondother wireless communication device within the second cluster, whereinat least one of the first response or the second response includes anacknowledgement (ACK), a block acknowledgement (BA), or a trainingfeedback frame.
 20. The method of claim 14, wherein the wirelesscommunication device is an access point (AP), and at least one of thefirst other wireless communication device or the second other wirelesscommunication device includes a wireless station (STA).